hinge on

noun

1. a jointed device or flexible piece on which a door, gate, shutter, lid, or other attached part turns, swings, or moves.
2. a natural anatomical joint at which motion occurs around a transverse axis, as that of the knee or a bivalve shell.
3. that on which something is based or depends; pivotal consideration or factor.
4. Also called mount. Philately. a gummed sticker for affixing a stamp to a page of an album, so folded as to form a hinge, allowing the stamp to be raised to reveal the text beneath.

verb (used without object), hinged, hing·ing.

5. to be dependent or contingent on, or as if on, a hinge (usually followed by on or upon): Everything hinges on his decision.

verb (used with object), hinged, hing·ing.

6. to furnish with or attach by a hinge or hinges.
7. to attach as if by a hinge.
8. to make or consider as dependent upon; predicate: He hinged his action on future sales.

noun

1. a device for holding together two parts such that one can swing relative to the other, typically having two interlocking metal leaves held by a pin about which they pivot
2. anatomy a type of joint, such as the knee joint, that moves only backwards and forwards; a joint that functions in only one planeTechnical name: ginglymus
3. a similar structure in invertebrate animals, such as the joint between the two halves of a bivalve shell
4. something on which events, opinions, etc, turn
5. Also called: mount philately a small thin transparent strip of gummed paper for affixing a stamp to a page

verb

6. (tr) to attach or fit a hinge to (something)
7. (intr; usually foll by on or upon) to depend (on)
8. (intr) to hang or turn on or as if on a hinge

n.

c.1300, “the axis of the earth;” late 14c. as “movable joint of a gate or door,” not found in Old English, cognate with Middle Dutch henghe “hook, handle,” Middle Low German henge “hinge,” from Proto-Germanic *hanhan (transitive), *hangen (intransitive), from PIE *konk- “to hang” (see hang (v.)). The notion is the thing from which a door hangs.

v.

c.1600, “to bend,” from hinge (n.). Meaning “turn on, depend” is from 1719. Related: Hinged; hinging.

n.

1. A jointed or flexible device that allows the turning or pivoting of a part, such as a door or lid, on a stationary frame.

Also, hinge upon. Depend or be contingent on, as in This plan hinges on her approval. This expression employs the verb hinge in the sense of “to hang,” as a door would hang on a hinge, a usage dating from the early 1700s.