apical angle
From ZooTerms (Dictionary of Invertebrate Zoology)
apical angle: 1. (Arthropoda: Insecta) The angle of a wing at its apex.
2. (Mollusca: Gastropoda) In a plane through the axis, that angle subtended between two straight lines that touch adjacent whorls on opposite sides near the apex; identical with the spire angle if whorls increase at a regular rate.
