kay /keɪ/exclamation 1noun 4forms 1 exclamation1 •(informal) a short form of "okay", used in speech to agree or to show you understand noun4 •The name of the Latin script letter K/k. •(informal) A kilometer. •(informal) A thousand of some unit (from kilo-). •(old-fashioned) Dated form of cay.Three small sandy kays on the reef, bearing this name, lie at the distance of about 5½ miles S.S.E. from Boca Chica. — 1839 formskays
