My brother and sister-in-law are arguing about whether "train" meaning locomotive and "train" meaning teach constitutes one word with two different meanings or if it's two different words. I said that the etymology appears to be the same, so it would be one word with two different meanings ... but the more I think about it, the less sure I am that this is correct. One's a noun, the other is a verb, so ... does that make it two different words?


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    So, in effect, you're asking for a definition of the word "word" in this context?
    – user867
    Feb 4, 2014 at 5:41
  • I hadn't thought of that, but I suppose I am ... what would constitute whether "train" - or any word - was one word or two: etymology, or parts of speech? Feb 4, 2014 at 5:49
  • This sounds similar to the problem that biologists have when defining new species. If two compatible groups of animals have differentiated and no longer interbreed, they are different species. Similarly, deciding whether two meanings constitute the same word depends on just how closely related those meanings are. Feb 4, 2014 at 15:43
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    I don't how how much linguists care about an engineer's perspective, but here it is: it should be a single word with multiple meanings since that's a robust way to uniquely and easily identify a particular word. If you consider different meanings as defining different words then you might need an arbitrary amount of information (context) in order to accurately describe the meaning and thus be clear about which word you are referring to. Not only that, but then you also get into the business of defining what "meaning" is, which is probably even more problematic.
    – Paul
    Feb 4, 2014 at 19:30
  • I usually consider it the same word if there is only one entry in the dictionary. So, by that standard, train is indeed one word, be it a noun or verb, but jack could be one of three words (but usually the first one, unless we are referring jackfruit, or else some armor). That may be a somewhat arbitrary way of looking at the problem, but at least I've left the final decision to experts.
    – J.R.
    Feb 12, 2014 at 21:07

5 Answers 5


This is a question that is discussed by eminent British linguist David Crystal in his article How many words?, in which he attempts to come up with a reasonably accurate count of the number of words in the English language. Basically, he says that no accurate number is possible because there is no universally-agreed definition of what constitutes a word. Here is an extract that addresses your question, but provides no definitive answer:

Is the lock on a door the same basic meaning as the lock on a canal? Should ring (the shape) be kept separate from ring (the sound)? Are such cases 'the same word with different meanings' or 'different words'? These are the daily decisions that any word-counter (or dictionary compiler) must make.

The article is here (pdf): www.davidcrystal.com/?fileid=-4890


Both possibilities are can be found. A word can get a new meaning simply by semantic change. That is, a word can take on meanings that are closely related as for instance the consequence of a thing or an act. There are a lot of possibilities how a word can develop new meanings.

The second possibility is two words have become identical in the course of time due to historical sound change or drop of syllables and other reasons. An example is the adjective fresh in the sense "fresh from the press/the oven". Most dictionaries have the meaning "insolent" in the entry of fresh. But that is actually a second word and it would need a second entry. "fresh" number 2, mostly in AmE, as in "Don't get fresh" must have been invented by German-American speakers who anglisized German frech (insolent) as "fresh". It is not seldom that one finds similar things, I mean that in a dictionary entry two different words are contained.


Actually, I didn't answer your question exactly, Laura. You asked whether train (noun, on railroads) and the verb to train someone (to teach) are the same word. The question is reasonable. But as in English dictionaries noun and verb and other word classes are treated in one entry one should say it is one word, especially as the etymological source is the same: Latin trah-ere to pull and according to etymonline from Vulgar Latin *traginare.

A locomotive pulls the wagons/carriages a train consists of. A coach training his team pulls them towards an efficient state of achievement.

But my personal view is that a noun is one word class and a verb another word class. So I would prefer the formuluation "a train" and "to train" are two different word classes from the same historical source.

  • why not combine your two answers into one?
    – Martin F
    Feb 4, 2014 at 22:34
  • When the posts are too long the edit-program behaves queerly.
    – rogermue
    Apr 22, 2014 at 17:57

It can be argued that the word "word" actually means a string of letters, so every meaning of train in every language is actually the same word.

In fact, Google defines "word" as "a single distinct meaningful element of speech or writing, used with others (or sometimes alone) to form a sentence and typically shown with a space on either side when written or printed." This meaning also implies that having different meanings doesn't make it multiple words.

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    So here is my thought: I was thinking that etymology was the key ... if you have a flower pot with two distinct roots, you'll get two distinct plants. If there's only one root, then it's all considered to be one plant, even if you can easily see all the differences - stem, leaves, petals, etc. It's the same with words - one root, much variety. Different forms of speech would make different word classes, but not necessarily different words, perhaps like the flower's petals would be a different color from, say, the leaves - but I can see that the waters are a bit muddy here! The joys of English! Feb 4, 2014 at 19:41

Homonyms are two words with the same name but different meanings. If they were two meanings for the same word, we would refer to them as something like polynotations.

So train and train are two different words, not two meanings for the same word.

  • You need to explain "polynotation" further!
    – Martin F
    Feb 4, 2014 at 22:51
  • Polynotation is a word I made up on the spot for multiple meanings for a singe word. I based it on connotation and denotation. If it were a useful concept, we would probably already have a well known word for it. I think that the fact that homonym is a word and polynotation isn't demonstrates that train and train are two different words, not two different meanings for the same word. If there is a correct term for what I'm calling polynotations, and it is used about as frequently as homonym, then I'm wrong.
    – jejorda2
    Feb 5, 2014 at 13:17
  • I'm all for new words when needed! Now you should move that discussion into you're answer.
    – Martin F
    Feb 5, 2014 at 16:45
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    Are you referring to polysemes? Feb 5, 2014 at 18:33
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    Today's quote from Wikipedia: The difference between homonyms and polysemes is subtle. Lexicographers define polysemes within a single dictionary lemma, numbering different meanings, while homonyms are treated in separate lemmata. Feb 5, 2014 at 19:22

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