thirteen

noun

1. a cardinal number, 10 plus 3.
2. a symbol for this number, as 13 or XIII.
3. a set of this many persons or things.

adjective

4. amounting to 13 in number.

noun

1. the cardinal number that is the sum of ten and three and is a prime numberSee also number (def. 1)
2. a numeral, 13, XIII, etc, representing this number
3. the amount or quantity that is three more than ten; baker’s dozen
4. something represented by, representing, or consisting of 13 units

determiner

5. 1. amounting to thirteenthirteen buses
   2. (as pronoun)thirteen of them fell

n.early 15c., metathesis of Old English þreotene (Mercian), þreotiene (West Saxon), from þreo “three” (see three) + -tene (see -teen). Cf. Old Frisian thretten, Dutch dertien, German dreizehn. Not an unlucky number in medieval England, but associated rather with the customary “extra item” (e.g. baker’s dozen). Superstitions began with association with the Last Supper, and the unluckiness of 13 sitting down together to dine (attested from 1690s). Most of the modern superstitions (buildings with floor “12-A,” etc.) have developed since 1890.