1. Enclosed within a hard shell, usually the skin of the last larval instar. Used of an insect pupa.
2. Constricted, narrowed, or compressed, as a segment of a blood vessel.
[Latin coarctātus, past participle of coarctāre, to compress, alteration of coartāre : co-, co- + artāre, to compress (from artus, tight, confined; see ar- in the Appendix of Indo-European roots).]
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