Trimming joist

from The Collaborative International Dictionary of English v.0.48

Joist \Joist\ (joist), n. [OE. giste, OF. giste, F. g[^i]te, fr.
   gesir to lie, F. g['e]sir. See {Gist}.] (Arch.)
   A piece of timber laid horizontally, or nearly so, to which
   the planks of the floor, or the laths or furring strips of a
   ceiling, are nailed; -- called, according to its position or
   use, {binding joist}, {bridging joist}, {ceiling joist},
   {trimming joist}, etc. See Illust. of {Double-framed floor},
   under {Double}, a.
   [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Trimming \Trim"ming\,
   a. from {Trim}, v.
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         The Whigs are, essentially, an inefficient, trimming,
         halfway sort of a party.                 --Jeffrey.
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   {Trimming joist} (Arch.), a joist into which timber trimmers
      are framed; a header. See {Header}. --Knight.
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