a. [f. Gr. τροχός wheel + -AL.]
1. Zool. Resembling a wheel; rotiform: as the trochal apparatus, disk, or organ of the Rotifera, an organ of locomotion consisting of two rings of cilia surrounding the mouth. b. Having a trochal apparatus, as a rotifer: TROCHATE (Cent. Dict.).
1841–71. T. R. Jones, Anim. Kingd. (ed. 4), 482. The space between the two layers of the trochal disk.
1888. Rolleston & Jackson, Anim. Life, 632. Class Rotifera. Unisegmental Vermes with a retractile trochal apparatus at the anterior end of the body.
1899. Syd. Soc. Lex., Trochal organ, the characteristic oral organ of the Rotifera.
2. Revolving like a wheel or top. rare–0.
1891. in Cent. Dict.
