What is the correct to write and/or? I have seen it written "and or" as two separate words and I think it looks odd.

  • 1
    There is nothing wrong with writing, in your recipe, "add a potato and/or an onion". It's concise and reasonably well understood. It is not, however, strictly "formal", and pedants will likely object if the construction is used in some hoity-toity context. Saying "add a potato and or an onion" is confusing and leaves the reader wondering if there is a typo.
    – Hot Licks
    Sep 6 '16 at 1:59

You'd be hard pressed to find a style guide that doesn't admonish you to drop “and/or” and choose either “and” or “or.”

In writing either and or or is usually adequate.

If a greater distinction is needed, another phrasing is available
         : X or Y, or both.



ELU: The difference between "and" and "and/or"

It is more common in technical,business,and legal writing.


There is no correct way; it depends on what style guide you are using.

However, at least in AmE, and/or is the vastly more common construction. If in doubt, I would choose and/or.

For more information, I'll point you to Wikipedia: http://en.wikipedia.org/wiki/And/or


This has been a debate for a long time at my work. I thought it was and, or. I was informed that a slash should be kept for forms. I will/will not attend.


"and/or" has the same logical value as "or", I always use "or" which is simpler and better looking. In fact, the slash sign "/" is not even part of the standard punctuation and looks terrible when replacing the comma in normal text. Another reason for discouraging "/" is its ambiguous interpretation: "A/B" could mean "A or B", but also "either A or B" (what logicians call an "exclusive or", sometimes encoded as "xor" as in the Latin "aut" as opposed to "vel", which is the usual inclusive "or").

  • But it's because we don't have the equivalents of 'aut' and 'vel' in English, that we need 'and/or' (or something) to make up for this lack.
    – peterG
    Sep 21 '17 at 18:31
  • ' ... the slash sign "/" is not even part of the standard punctuation ...' is very questionable (and lacking supporting evidence); CED includes a definition without caveats for and/or. Sep 21 '17 at 19:01
  • @peterG English has "either" which is very useful: so "A or B" is "A vel B", whereas "either A or B" is "A aut B", the problem with "and/or" is that it is logically equivalent to "or" ("vel") and therefore redundant. Sep 21 '17 at 20:51
  • @EdwinAshworth ok, "/" can be used as punctuation. According to the CD "and/or" means "either and or or". But this is strange as "either A or B" is exclusive which means that A and B should never occur together, but "or" is inclusive (otherwise it would be equivalent "either...or...") which means that "or" is satisfied every time the "and" is satisfied (so the and is redundant). Hence, either "and/or" is inconsistent (when "/" means "exclusive or") or "and/or" is redundant (when "/" means "(inclusive) or"). Both cases imply that there is never the need for "and/or". Sep 21 '17 at 21:03
  • @Oskar But it's all well and good offering 'either' and so on, but the fact remains that in everyday use, 'or' carries with it (rightly or wrongly) the strong implication of 'exclusive-or', hence the need for another term to clearly mean 'inclusive-or'.
    – peterG
    Sep 21 '17 at 21:23

In writing the phrase and/or, for example in a sentence as: I need to purchase a new item and/or return this one. the sentence would literally translate to: I need to purchase a new item and and or or return this one.

To properly designate the intention of "and/or" it would be written: I need to purchase a new item/return this one.

Nonetheless, the usage of the phrase is highly regarded as inappropriate/poor writing.

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    Regarding your answer, can you explain why you think "and/or" translates as "and and or or"? It's not a widely held view. Your 2nd para also seems wrong: the slash is normally interpreted as an "or", so your designation leaves out the "and" option. NB: you can add further detail to your answer by clicking on the edit link. :-) Sep 6 '16 at 1:01

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