Carpentry. [See COG v.2; the form of the word is app. due to association with the ‘cogs’ of a wheel, viewed as teeth or projections fitting into counter-depressions.] A projection or tenon on the end of a beam, which is received into a corresponding notch or mortice on the surface of another beam or support; used in tailing joists to wall-plates, making a scarf-joint, etc. Cog-hold: a fastening or connection by means of a cog.
1856–8. Archit. Publ. Soc. Dict., s.v. Coghold, The bearing timbers ought to be placed upon pieces of stone as templates built into the walls, and be made to take a coghold of the templates so as to enable them to tie and stay the walls, by means of the cogs.
