Birdsmouth

//ˈbɜːdsmaʊθ// noun, verb

noun, verb ·Rare ·Advanced level

Definitions

Noun
  1. 1
    A notch cut into the underside of a rafter to ensure that it does not move when resting on the wall plate running across the top of a wall; a similar notch in other timber components.

    "Support the veneer stack on a ¾-in.-thick board with a narrow V notch cut into one edge. This board is called a birds-mouth, and the V notch provides clearance for the blade while the work is supported for cutting."

Verb
  1. 1
    To cut a birdsmouth into a rafter or similar timber component.

    "The end of the common rafter is birdsmouthed and nailed to the pole plate."

Example

More examples

"Support the veneer stack on a ¾-in.-thick board with a narrow V notch cut into one edge. This board is called a birds-mouth, and the V notch provides clearance for the blade while the work is supported for cutting."

Etymology

From bird + -s- + mouth, from its appearance.

Related phrases

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.