Tagmas

Part of speech: noun

Definitions

1. Segments or distinct sections of an arthropod's body that are specialized and combined to form functional units
2. Modular body parts found in arthropods where individual segments are grouped and fused to carry out specific roles
3. Divisions within the body structure of certain invertebrates, comprising fused segments that perform coordinated functions

Etymology: "Tagma" comes from the ancient Greek "tagma", meaning "that which has been arranged" or "a division of troops", from the verb "tassein", "to arrange or put in order". Greek military writers used it for a body of soldiers drawn up in a formation, and the sense of a discrete, ordered unit carried over into zoology. In biology, the word was adopted in the 19th century for the groups of body segments found in arthropods such as insects, crustaceans and spiders. A tagma is a region in which neighbouring segments have fused and specialised for shared work: in insects the head, thorax and abdomen are tagmata, and in crustaceans and spiders the body is often split into cephalothorax and abdomen. The modern English word was formed directly from the Greek, so it is a learned coinage rather than a word that passed through everyday speech.

Synonyms: body segments, body regions