This is hard to describe, but I'm curious about what the proper word is for these thingies in English.

So I searched for a picture on Google and circled what I'm referring to with red:

Puzzle piece with the questionable parts circled with red.

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    My brain has decided they're called "knobs", but I've absolutely no proof anyone else calls them that. Nov 8, 2011 at 13:15
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    We always called them "bobbles" (or perhaps "blobbles").
    – Colin Fine
    Nov 8, 2011 at 13:47
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    Pretty obscure. I don't think most English speakers know a word for that.
    – Joe
    Nov 8, 2011 at 14:40
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    The ends of the pieces of toy train tracks are called "male" and "female" where they connect. The connection itself is called a "mating connection." I would think the same concept would apply to jigsaw puzzles.
    – user70809
    Jun 3, 2015 at 17:49
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8 Answers 8


This kind of puzzle is called a jigsaw puzzle, and the corresponding Wikipedia page uses the terms tabs and blanks. (The parts you've circled are the tabs.)

Looking further throws up many citations for "tabs": this book on DNA computing calls them jigsaw tabs (and pockets), this book on programming also mentions interlocking tabs, this issue of Make magazine calls them jigsaw tabs (and slots), and there are lots of other books. There seems to be more consensus on what to call the circled pieces you want (tabs) and less on what to call the other kind (blanks, pockets, slots, indents...).

You can also trawl through search results for jigsaw (tab OR tongue OR outie), to compare the answers suggested. (Need to look at each result individually to make sure the word is used in the right context. In fact most results aren't about the context we want. :-))

However, it is also a fact that there is no universally accepted terminology. For instance, this book on the history of jigsaw puzzles says on page 10 that

Despite a few attempts at a comprehensive classification of piece shapes and cutting designs, there is still no generally accepted nomenclature. Manufacturers use a variety of terms, as do puzzlers. Puzzle pieces can have "loops" and "sockets", "knobs" and "holes", "tabs" and "slots", "keys" and "locks", or any of several other alternative designations.

  • @Venemo: Unfortunately, I just updated my answer to show that blanks may not be universal. :-) But tabs seems to be used widely. Nov 8, 2011 at 12:07
  • How do you call the act of connecting the pieces, i.e. "some repeating patterns makes it harder to compose the puzzle"? Jul 16, 2013 at 14:21
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    Just as a curiosity - I have never, ever, ever heard them referred to as either tabs or blanks ..... and I work in a related software engineering field.
    – Fattie
    Mar 27, 2014 at 9:24
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    Hi Shree! - every single jigsaw puzzle (since perhaps 1995, I'm not sure) is made using software. The only engineers working in "jigsaw construction" are, indeed, programmers. Other than a handful of hand-made wooden jigsaw cutters, the only people who would use "jigsaw terminology" are programmers. (Note you reference a programming book?) Are you a native English speaker by the way? Regarding google searches, I find they have no relation at all to actual-usage on the street; you tend to find a few formalish references. Also, see my comment on Matt's answer below.
    – Fattie
    Mar 27, 2014 at 9:42
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    Not having thought of this before, I would have guessed tabs and notches (they aren't really slots, which are what tabs are often inserted into).
    – Drew
    Jan 30, 2021 at 0:21

Speaking as a fully-qualified jigsaw puzzle solver, I can say that the standard word is an outie. Terminology shared with belly-buttons, except normally only jigsaw outies interlock with innies.

According to this glossary people also call them tabs or knobs, but the problem there is they don't have an obvious term for the corresponding innie, so I'd stick with outie. A jigsaw is a game anyway, so there's nothing wrong with using childish terminology.

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    Innie and outie sounds a bit more casual than tab and blank.
    – Venemo
    Nov 8, 2011 at 12:06
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    Oh, before your edit I thought that "fully-qualified jigsaw puzzle solver" meant that you had participated in some state-/national-level jigsaw puzzle-solving competitions or something like that. :-) I would be disappointed to learn that no such thing exists. Nov 8, 2011 at 12:19
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    @ShreevatsaR: Nah - my qualifications aren't quite so formally-recognised. But I did spend a lot of time in hospital throughout my childhood, and there wasn't much else to do there for several weeks every year! Nov 8, 2011 at 12:59

All I can suggest is tongue, as in the joint in carpentry known as tongue and groove.

  • You make me think, "dog" wold be a great term here. (Since it is, exactly that, a dog.) I wonder does anyone know, what's the female version of a dog called? Probably a sailor or old-days carpenter would know this?
    – Fattie
    Mar 27, 2014 at 9:44
  • A 'female version of a dog' is surely a bitch @Fattie Aug 13, 2017 at 20:06
  • You know @Clare "dog" also means (ask, say, a sailor or engineer), a "projection" that is used to grab or stop something - picture something like, oh, a coat-hook or a stick of metal poking out. Example, imagine a shuttle or something that whips along on some steel rail: at each end there's like a lump of metal sticking out (think like a dowel) that stops it moving at the end, you call that thing a "dog"........ indeed it occurs to me the opposite of that type of "dog" would be a "notch" probably.
    – Fattie
    Aug 13, 2017 at 21:55

I believe 'tenon' and 'mortice' are the appropriate technical terms.

  • That's interesting, considering everything else suggested on this page doesn't mention either. What leads you to this conclusion? Mar 14, 2012 at 21:25
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    @MattЭллен: I don't know about jigsaw puzzles, but these are the preferred terms in woodworking en.wikipedia.org/wiki/Mortise_and_tenon. I, personally, would find it natural to borrow terms from woodworking (if they didn't exist already). And so, I +1'd it. But that's just what I'm inclined to do.
    – prash
    Mar 14, 2012 at 21:31
  • but then, I'm not an expert at woodworking either. Though "mortice and tenon" is a very specific kind of joint, the same terms are used for a few other types of joints.
    – prash
    Mar 14, 2012 at 21:53
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    +1: Given that jigsaw puzzles originated in woodworking, I think this is a plausible conjecture. I am used to seeing it spelled mortise, however, but either is correct.
    – Robusto
    Apr 8, 2012 at 14:29
  • It is exactly, precisely correct that tenon and mortice are appropriate technical terms. I don't know if you can say they are "the" technical terms.
    – Fattie
    Mar 27, 2014 at 9:26

Looking at the Wikipedia article on jigsaw puzzles, they use the word tab:

Some fully interlocking puzzles have pieces all of a similar shape, with rounded tabs out on opposite ends, with corresponding blanks cut into the intervening sides to receive the tabs of adjacent pieces.

(emphasis added)

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    Who cares what someone writing on Wikipedia, used to describe the issue? So what? The person writing there is not saying "the word usually used is 'xyz', the person writing there is simply describing them. (Exactly as the OP describes them in some other way.)
    – Fattie
    Mar 27, 2014 at 9:25

There's a very important point here:

In English, it's reasonably common that - strangely enough - there IS NO WORD for a certain fairly common thing.

(There's possibly actually a term for this phenomenon - like "grasp words" or "thingy words" or something.)

Note for example, Justin's first comment on the question - which is totally correct and typical.

I have never, ever, ever heard them referred to in any way, in English, other than something like "the thingy that sticks out" "the hole thing on the edge" "the whatever tonguey thingy"

Note that even if you look at software (like the actual computer code, in c# of whatever, relating to machines that cut puzzles) you just seeterms like TheOutThingy OneOfTheHoleThings and so on.

Again - in my opinion - among English speakers it's reasonably common that - strangely enough - there IS NO WORD for a certain fairly common thing. We stick with "thingy phrases" and sort of deliberately don't settle on a word. IMO the - thingies - on jigsaws are a perfect example of this.

So, IMO, there is literally no word for these in English - even among jigsaw aficionados or in the games industry.

{A small point: Note too that the jigsaw-puzzle industry is largely German, as it happens, so you could possibly look to the German language for guidance here, if you're trying to "decide on" what we should all call these thingies.}

{Another small point - note that, wildly confusingly, "jigsaw puzzles" are called "jigsaw puzzles" in certain English speaking areas, BUT, are called .. wait for it .. "puzzles" in other English speaking areas.}

  • Thanks, nice thought! I've already settled with 'tab' and 'blank' (because they were shorter), but it's always nice to see more insight into English :)
    – Venemo
    Mar 27, 2014 at 12:05
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    Right. In my family (British English) we've always called them "the sticky-out bits". Although there might be specific terms which are technically correct, they're not likely to be widely recognised.
    – A E
    Oct 20, 2014 at 11:50
  • yeah "sticky-out bits" is the highly technical term :-)
    – Fattie
    Oct 21, 2014 at 12:11
  • German is just as confused: Noppe, Nase, Knopf, Zapfen, Ausbuchtung for 'outies' [~bobble, nose, button, tongue in the woodworking sense, bulge] and 'Loch (Nasenloch, Knopfloch), Einbuchtung' [hole x3, indentation] for the other one (I'd go with tab and hole myself). Mar 6, 2020 at 14:07
  • I would just call them ''links'' if I had to use a word in English. Jan 31 at 19:54

Another way of calling it would be male plug or male connector.

I'm coding a puzzle game right now and I've found this thread while searching for an appropriate variable name. I've decided to go with plug, because I was looking for a generic term that describes both tabs and blanks, innie and outie, ricky and morty etc. Plugs can be male or female, where male corresponds to tab and female to blank.

And here's a little code for fellow software developers:

enum PlugType {

enum PlugSide {
  • While this is interesting, it does not answer the question.
    – Davo
    May 3, 2019 at 12:44
  • In my humble opinion it does, as one way you can call this thing is a plug (which answers the question). Maybe it's not a correct term as far as manufacturers call it, but I know a lot of software developers visit this site for the same reason I did and I wanted to help them. Maybe I went to far with placing the code here :) May 3, 2019 at 13:00
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    The question was specifically about the extended, or male portions. If you edit your answer to clearly indicate the coupled terms male or female plugs, I would upvote it. But not as it is, with just plugs. And I actually liked your coding example.
    – Davo
    May 3, 2019 at 13:03
  • OP here. My original question was also for a puzzle game that I coded. :) If you're interested, you can find it here: github.com/Venemo/puzzle-master I went with the accepted "tabs" and "blanks" but I guess "plug" could also work as a more generic term.
    – Venemo
    May 3, 2019 at 15:36
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    Funny That you ended up here for the same reason as me... Here is my Enum: Public Enum EdgeType As Integer None = 0 Male = 1 Female = 2 End Enum
    – Paul Ishak
    Jul 2, 2020 at 13:46

I am a woodworker and I often happen to explain that I craft puzzles without those joints. Native speakers do not assimilate those Wikipedia's tabs and blanks. So forget them if you want a layman to grasp the meaning the first time. Instead, I use figurative onion or bulb or protruding onion-shaped bulge.

Edit. Another comparison is a peninsula contrasted to the bay or fjord to which it fits.

  • Hello, Przemyslaw. Please check at the Help Center and on ELU.Meta. ELU deals with standard (widely recognised) usages only, not novel suggestions, however ingenious / appealing. If you can find a reasonable reference supporting your figurative usages here, it will make this a valid answer. Note that 'thumbs' and 'bays' looks a reasonable suggestion ... but they're not idiomatic terms (with jigsaws ... they are with lakes), so off-topic. Jan 29, 2021 at 16:15
  • @EdwinAshworth No, I have learnt these usages through paving my way to the clearest explanations to others. But if it stays here maybe it will become a source for reference:-) BTW I do not have such a visual inverse-bulb term for the female socket. The suggested "bay" seems one of my favorite. Jan 29, 2021 at 16:28

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