Meaning of rule joint

rule' joint"

Pronunciation: [key]
  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.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.