single—adjective

1. only one in number; one only; unique; sole: a single example.
2. of, relating to, or suitable for one person only: a single room.
3. solitary or sole; lone: He was the single survivor.
4. unmarried or not in a romantic relationship: a single man.
5. pertaining to the unmarried state: the single life.
6. of or noting a parent who brings up a child or children alone, without a partner.
7. of one against one, as combat or fight.
8. consisting of only one part, element, or member: a single lens.
9. sincere and undivided: single devotion.
10. separate, particular, or distinct; individual: Every single one of you must do your best. It's the single most important thing.
11. uniform; applicable to all: a single safety code for all manufacturers.
12. (of a bed or bedclothes) twin-size.
13. (of a flower) having only one set of petals.
14. British.of standard strength or body, as ale, beer, etc.
15. (of the eye) seeing rightly.

—verb (used with object), sin·gled, sin·gling.

16. to pick or choose (one) from others (usually followed by out): to single out a fact for special mention.
17. Baseball.
    1. to cause the advance of (a base runner) by a one-base hit.
    2. to cause (a run) to be scored by a one-base hit (often followed by in or home).

—verb (used without object), sin·gled, sin·gling.

18. Baseball.to hit a single.

—noun

19. one person or thing; a single one.
20. an accommodation suitable for one person only, as a hotel room or a table at a restaurant: to reserve a single.
21. a ticket for a single seat at a theater.
22. British.
    1. a one-way ticket.
    2. a steam locomotive having one driving wheel on each side.
23. singles,people who are unmarried or not in a romantic relationship, especially if relatively young: It's not uncommon for singles to feel lonely on Valentine Day.
24. Baseball. Also called one-base hit.a base hit that enables a batter to reach first base safely.
25. singles, (used with a singular verb)a match with one player on each side, as a tennis match.
26. Golf..
27. Cricket.a hit for which one run is scored.
28. Informal.a one-dollar bill.
29. Music.
    1. a phonograph record, CD, or cassette usually having two songs: I probably won't buy the single.
    2. one of the songs recorded on a single: a hit single.
    3. a song released or promoted separately from the rest of the album to which it belongs: A viral video put that single back on the charts.
30. Often singles. Textiles.
    1. reeled or spun silk that may or may not be thrown.
    2. a one-ply yarn of any fiber that has been drawn and twisted.

Origin: 1275–1325; late Middle English (adj.), Middle English sengle < Old French < Latin singulus individual, single (usually in the plural singuli one apiece), derivative of *sem- one (see simplex)

—Related forms
qua·si-sin·gle, adjective
qua·si-sin·gly, adverb
un·sin·gle, adjective

Can be confused: signal singlesingle singular

—Synonyms
1. distinct, particular. 3. isolated. 4. unwed. 16. select. 19. individual.