yard-arm noun. ['jɑ:dɑ:m] L15.
[from YARD noun² + ARM noun¹.]
Nautical. Either end of a ship's yard; the part of either end of a yard which is outside the sheave-hole.
when the sun is over the yard-arm slang at the time of day when it is permissible to begin drinking. yard-arm and yard-arm, yard-arm to yard-arm (of two ships) so close to one another that their yard-arms touch or cross.

Comb.:
yard-arm iron a metal ring attached to each yard-arm to house the studding-sail boom.

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