singular

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. Being only one; individual.
2. adj. Being the only one of a kind; unique.
3. adj. Being beyond what is ordinary or usual; remarkable.
4. adj. Deviating from the usual or expected; odd. See Synonyms at strange.
5. adj. Grammar Of, relating to, or being a noun, pronoun, or adjective denoting a single person or thing or several entities considered as a single unit.
6. adj. Grammar Of, relating to, or being a verb expressing the action or state of a single subject.
7. adj. Logic Of or relating to the specific as distinguished from the general; individual.
8. n. Grammar The singular number or a form designating it.
9. n. Grammar A word having a singular number.

Century Dictionary and Cyclopedia

1. Being a unit, or one only; single.
2. Separate or apart from others; alone.
3. Pertaining to solitude, or separation from others; concerned with or involving solitude.
4. Pertaining to one person or thing; individual; also, pertaining to individual persons or things; in logic, not general; being only in one place at one time.
5. In grammar, denoting or relating to one person or thing: as, the singular number: opposed to dual and plural. Abbreviated singular
6. Having no duplicate or parallel; unmatched; unexampled; unique; being the only one of its kind.
7. Out of the usual course; unusual; uncommon; somewhat strange; a little extraordinary: as, a singular phenomenon.
8. Hence Of more than average value, worth, importance, or eminence; remarkable; fine; choice; precious; highly esteemed.
9. Not complying with common usage or expectation; hence, eccentric; peculiar; odd: as, he was very singular in his behavior.
10. In mathematics, exceptional. In geometry and algebra, having peculiar non-metrical properties. See singularity, 3.
11. Synonyms and Unwonted, exceptional, unparalleled.
12. Strange, Odd, etc. See eccentric.
13. n. That which is singular, in any sense of the word; that which is alone, separate, individual, unique, rare, or peculiar. See singular, a.
14. n. In grammar, the singular number.
15. n. In hunting, a company or pack: said of boars.
16. n. In logic, that which is not general, but has real reactions with other things. Scotus and others define the singular as that which is here and now—that is, only in one place at one time. The Leibnitzian school define the singular as that which is determinate in every respect.

Wiktionary

1. adj. Being only one of a larger population.
2. adj. Being the only one of the kind; unique.
3. adj. Distinguished by superiority, coming across as such.
4. adj. Being out of the ordinary, coming across as such.
5. adj. Referring to only one thing or person.
6. adj. Having no inverse.
7. adj. Having the property that the matrix of coefficients of the new variables has a determinant equal to zero.
8. n. A form of a word that refers to only one person or thing.

GNU Webster's 1913

1. adj. Separate or apart from others; single; distinct.
2. adj. Engaged in by only one on a side; single.
3. adj. Existing by itself; single; individual.
4. adj. Each; individual.
5. adj. Denoting one person or thing; ; -- opposed to dual and plural.
6. adj. Standing by itself; out of the ordinary course; unusual; uncommon; strange.
7. adj. Distinguished as existing in a very high degree; rarely equaled; eminent; extraordinary; exceptional.
8. adj. Departing from general usage or expectations; odd; whimsical; -- often implying disapproval or censure.
9. adj. Being alone; belonging to, or being, that of which there is but one; unique.
10. n. An individual instance; a particular.
11. n. The singular number, or the number denoting one person or thing; a word in the singular number.

WordNet 3.0

1. adj. being a single and separate person or thing
2. adj. unusual or striking
3. adj. grammatical number category referring to a single item or unit
4. adj. the single one of its kind
5. n. the form of a word that is used to denote a singleton
6. adj. composed of one member, set, or kind
7. adj. beyond or deviating from the usual or expected