Definitions

Anterior region of body, commonly limited behind by major articulation. In cirripeds large sac-like body in position of "head" in front of (and rostral from) thoracic limbs, supporting trophi and commonly first cirri. [Moore and McCormick, 1969]
Anterior region of body, commonly limited posteriorly by major articulation. In cirripeds, large saclike body in position of "head" in front of, and rostral to, thoracic appendages, supporting trophi and usually 1st cirri.
(syn. prosoma) [McLaughlin, 1980]
Collective term for the combined cephalasome and metasome in copepods. [Brusca and Brusca, 2002]
(Taxon-specific: Subclass Copepoda) The anterior tagma of the body, up to the major articulation; comprising the cephalosome and either four (podoplean tagmosis) or five (gymnoplean tagmosis) free pedigerous somites. [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Copepoda) The part of the adult copepod body anterior to the major body articulation. [Ferrari and Dahms, in press]
(Taxon-specific: Class Ostracoda) In one interpretation of body segmentation, anterior of two divisions (tagmata) of body (prosome, urosome); consists of region anterior to flexure point of body (or anterior to genital complex in forms without body articulation) and comprises cephalosome (head and fused thoracic segments) and metasome (thoracic segments anterior to flexure point). [Stachowitsch, 1992]