n. A plant which blooms.Having the character of the style of female dress introduced by Mrs. Bloomer of New York in 1849-50: as, a bloomer costume; a bloomer hat.n. A dress or costume for women, the distinctive features of which are a short skirt, loose trousers buttoned round the ankle, and a broad-brimmed, low-crowned hat. Specificallyn. A bloomer hat.n. plural The articles composing a bloomer costume: as, to be dressed in bloomers.n. A woman who assumes such a dress.