Zool. [ad. Gr. τρίαινα trident.] A kind of sponge-spicule.
Variously described as ‘a rhabdus having at one end three prongs or “cladi” diverging at equal angles,’ and ‘a tetraxon spicule with 1 long and 3 equal shorter tangential rays.’
1887. Sollas, in Encycl. Brit., XXII. 417/1. (Sponges) A particular case of the cladose rhabdus,… of the most frequent occurrence, is the triæne.
Hence Triænostrongyle [Gr. στρογγύλος rounded], a triæne in which the main arm is blunt at the end; Triænostyle [Gr. στῦλος pillar, STYLE], one in which it is sharp; Triænotyle [Gr. τύλη cushion], one in which it is blunt and rounded.
1909. in Cent. Dict. Supp.
