单词 tetract 释义 tetract, a. and n. Zool.|ttrkt|[f. tetra- + Gr. ἀ-, ἀῑ- ray.]a. adj. Having four rays or branches; quadriradiate. b. n. A four-rayed sponge-spicule. So tetractinal a., tetractine a. and n., tetractinose a.1886Proc. Zool. Soc. 21 Dec....