Definition of "tern"

Any of various seabirds of the subfamily Sternidae (of the family Laridae) that are similar to gulls but are smaller and have a forked tail.  examples

(dated or obsolete) A thing with three components; a set of three things.

1. (gambling, dated) A lottery prize resulting from the favourable combination of three numbers in the draw.  quotations  examples

   Quotations

   • And yet, now even, if Madonna willed, / She'd win a tern in Thursday's lottery, / And better all things.

     1856, Elizabeth Barrett Browning, “Seventh Book”, in Aurora Leigh, London: Chapman and Hall, […], published 1857, page 319

(chiefly botany, rare) Consisting of three components; ternate, threefold, triple.