What is a beam, into which are framed the ends of headers in floor framing, as when a hole is to be left for stairs, or to avoid bringing joists near chimneys, and the like. See Illust. of Header called?

trimmer — (Arch.) A beam, into which are framed the ends of headers in floor framing, as when a hole is to be left for stairs, or to avoid bringing joists near chimneys, and the like. See Illust. of Header. (Webster's 1913.)