Calque of complex, by Hermann Weyl. Complex comes from the Latin complexus (“braided together”) (from com- (“together”) + plectere (“to weave, braid”)), while symplectic comes from the corresponding Ancient Greek sym-plektos (συμ (sum), variant of σύν (sún) + πλεκτικός (plektikós), from πλέκω (plékō)). In both cases the suffix comes from Proto-Indo-European *plek-.
Previously, the “symplectic group” had been called the “line complex group”.
symplectic (not comparable)
- (mathematics) Describing the geometry of differentiable manifolds equipped with a closed, nondegenerate 2-form