singular

Short definition from Wiktionary

Adjective

1. 1
   Being only one of a larger population; single, individual.
2. 2
   Being the only one of the kind; unique.
3. 3
   Distinguished by superiority: peerless, unmatched, eminent, exceptional, extraordinary.
4. 4
   Out of the ordinary; curious.
5. 5
   Referring to only one thing or person.
6. 6
   Having no inverse.
7. 7
   Having the property that the matrix of coefficients of the new variables has a determinant equal to zero.
8. 8
   Not equal to its own cofinality.
9. 9
   Each; individual.
10. 10
    Engaged in by only one on a side; single.

Noun

1. 1
   A form of a word that refers to only one person or thing.
2. 2
   That which is not general; a specific determinate instance.