hinge / hinj/ • n. a movable joint or mechanism on which a door, gate, or lid swings as it opens and closes, or that connects linked objects. ∎ Biol. a natural joint that performs a similar function, for example that of a bivalve shell. ∎ a central point or principle on which everything depends: this period can be called the hinge of history. ∎ a small piece of gummed transparent paper used to affix a stamp to a page in an album.• v. (hing·ing) [tr.] (usu. be hinged) attach or join with or as if with a hinge: the ironing board was set into the wall and hinged at the bottom | [as adj.] (hinged) a pocket watch with a hinged lid. ∎ [intr.] (of a door or part of a structure) hang and turn on a hinge: the skull's jaw hinged down. ∎ [intr.] (hinge on) depend entirely on: the future of the industry could hinge on the outcome of next month's election.DERIVATIVES: hinge·less adj.
1. The surface region of a fold about a hinge line, which occupies the area of maximum curvature.
2. In Brachiopoda and lamellibranchs, the area of the commissure where the two valves of the shell are permanently in contact. In those articulate brachiopod (Articulata) shells where the whole width of the posterior part of the commissure remains in contact during opening the shell is said to be ‘strophic’. In those brachiopods where the hinge axis passes through the teeth and sockets, and these represent the fulcra, the shell is said to be ‘non-strophic’.