from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A distinct section of an arthropod, consisting of two or more adjoining segments, such as the cephalothorax of a spider.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A specialized grouping of arthropodan segments, such as the head, the thorax, and the abdomen with a common function.

from The Century Dictionary and Cyclopedia

  • n. In botany, a general term applied by Pfeffer to all the various theoretical aggregates of chemical molecules out of which vegetable structure is built up, thus embracing under one head the pleon, micella, and micellar aggregate. See micella, pleon, syntagma.


Greek, arrangement, from tassein, tag-, to arrange.
(American Heritage® Dictionary of the English Language, Fourth Edition)
Ancient Greek τάγμα (tagma, "something which has been ordered or arranged") (Wiktionary)



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