The Collaborative International Dictionary
Acraspeda
Acraspeda \A*cras"pe*da\, n. pl. [NL., fr. Gr. 'a priv. + ? border.] (Zo["o]l.) A group of acalephs, including most of the larger jellyfishes; the Discophora.
Wiktionary
acraspeda
n. (context zoology English) A group of acalephs that includes most of the larger jellyfish