feet, foot

   "Accompanied by Interior Secretary Gale Norton, the President also stopped at the 275-feet-high General Sherman Tree, a sequoia thought to be one of the largest living things on Earth" (Los Angeles Times). It is a quirk of English that when one noun qualifies another, the first is normally singular. That is why we talk about toothbrushes rather than teethbrushes and horse races rather than horses races. Exceptions can be found-systems analyst, singles bar-but usually these appear only when the normal form would produce ambiguity. When a noun is not being made to function as an adjective, the plural is the usual form. Thus a wall that is six feet high is a six-foot-high wall. For a discussion of the punctuation distinction, see hyphen in the appendix.