rule joint

noun
  1. (in carpentry and joinery) a joint between two hinged pieces, as between the center and end leaves of a table, consisting of a quarter round and fillet fitting against a cove and fillet.
  2. a pivoted joint between two strips of wood placed end to end, as in a carpenter's folding rule.

Origin of rule joint

First recorded in 1775–85
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018