Psycholinguistically, a lemma is an abstract conceptual form of a word. However from a lexicographic perspective, the lemma is merely the aorist or canonical form of a word.

In English, the lemma of a verb is the 3rd person singular form; for a noun, it's the singular form.

However for multi-word expression, we might need to use the plural form of a noun within the expression, e.g. "kick_one's_heels". Even if we don't consider multi-word expression to constitute a lemma, we have other inconsistencies of the criteria to give lemma status to a word, e.g. hooved(adj) vs hoofed(adj).

The difficulty of selecting the "canonical" word form as the lemma increases when dealing with morphological more sophisticated languages such as Turkish too.

What is a notion of lemma? How is it scientifically defined? Citations will be much appreciated.

  • 3rs person singular present. For nouns it's not the singular for pluralia tantum such as scissors, pants, trousers, spectacles, etc. though a singular for each of those may also have an entry. Normal dictionaries group multi-word expressions into the entries for one of the words so they safely avoid having to lemmatize them. Georgian dictionaries present a case of a language where there is not agreement of which form is the lemma for verbs. Mine all use the verbal noun in perfective and/or imperfective form whereas Wiktionary uses 1st person singular present indicative. Commented Jul 29, 2013 at 9:54
  • I was always under the impression that the infinitive was the "canonical form" of a verb. (ie, "to be", rather than "he is") Is there another term that describes what the infinitive is?
    – Ryno
    Commented Jul 29, 2013 at 21:55
  • 2
    @Ryno: Some languages have no infinitive, some have multiple infinitives, some have finite infinitives! You could surely make a good new question about infinitives. Often the lemma is the form with the fewest inflectional affixes - but not always. This makes the lemma the usable form closest to the stem, which often cannot be used in a bare form. In fact for these reasons I doubt that this is a psycholinguistics question at all because there's some amount of arbitrariness where somebody decides which form to use as a lemma. Commented Jul 30, 2013 at 3:21
  • Sorry, I meant to imply "in english", but yes, that would make a good question :)
    – Ryno
    Commented Jul 30, 2013 at 3:27
  • 2
    @hippietrail, I agree, this is not about the psycholinguistic definition of lemma, but the lexicographic one. A psycholinguistic lemma does not have a phonological form. Edited the question.
    – dainichi
    Commented Jul 30, 2013 at 8:26

2 Answers 2


First of all your statement:

In English, the lemma of a verb is the 3rd person singular form

is incorrect. The 3rd person singular of an English verb would be "he asks", "he digs" and "he is". Id don't know any dictionary to use this form. So, it probable the infinitive rather than the 3rd person singular although in English it's hard to guess sometimes. See wikipedia article also:

In English it usually is the full infinitive (to go) although alphabetized without 'to' (go)

All person except the 3rd person singular coincide usually with the infinitive, with possible exception the verb "to be":
I am
you are
he is
BUT to be.

Anyway, to your question now the same link of Wikipedia just answers your question but I guess you validated the answer as complete enough:

In morphology and lexicography, a lemma (plural lemmas or lemmata) is the canonical form, dictionary form, or citation form of a set of words

In other words it says that lemma is the

  • canonical form meaning the form of word that is standardized, deprived of most conjugation ending and transformation and meant to be an anchor for all searches involving all forms this word might appear.
  • dictionary form just means it's the form you look up in a dictionary for the above reason (easier to search for)
  • citation falls into the same category as the dictionary form: easier to cite.

The second part of your question which you express your doubts about the inconsistencies of the criteria to give lemma status to a word, is exactly that.

  • at some point the original lemma cannot deal exactly with the intend it was used initially, meaning to be searched easily. So, then lexicographer often add new entries which seems to break the lemma contract but they stick to the general rule of a standardized way to search a word.
  • This explains also cases, where multiple lemmas seem to address the same (morphologically) word. Then, there might be a shift in which part of speech the two words belong to, e.g. verb vs noun etc.

How is it scientifically defined? I don't think there is a large science behind it, it's just a convention that is used to refer to words and search them easily. It's like asking why the words are look up in this alphabetical order and not another order, e.g. by phonology etc?


In mathematics, the word "lemma" has a completely different meaning. It refers to a preliminary result, not necessarily of interest in itself, which is then used to prove the main result, which is usually called a "theorem."

  • 2
    Welcome to Linguistics.SE. This site is about the natural properties of languages, and the terminology we discuss is not about Mathematics, but about Linguistics. So, this post barely addresses the question asked. Further info on Wikipedia Commented Sep 4, 2016 at 21:54

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.