adminiculum
/ˌadmɪˈnɪkjʊləm/noun
1 Entomology. Originally: each of a number of minute spines or processes on the abdominal surface of certain subterranean insect pupae, used in locomotion (usually in plural; now rare ). Later also: an unpaired accessory sclerite in the genitalia of certain male flies.
2 Zoology and Palaeontology. Each of a number of tapering processes on the internal surface of the shell of certain articulated brachiopods. Usually in plural.
Origin
Early 19th century; earliest use found in William Kirby (1759–1850), entomologist and naturalist. From classical Latin adminiculum prop, support, in scientific Latin also accessory organ of a plant used for support, defence, etc. (G. A. Scopoli Fundamenta botanica 20).