noun
Hemichordata; hemichordates
A phylum of marine deuterostome animals, including acorn worms and graptolites. Used in biological and taxonomic contexts.
半索動物門にはギボシムシ類が含まれる。
The phylum Hemichordata includes acorn worms.
From 半 (half) + 索 (cord) + 動物 (animal) + 門 (phylum), referring to the stomochord, a structure once thought to be a notochord-like cord.