1
general::
Also, at the back of;in back of. Behind; also, supporting. For example, The special brands were stored back of the counter, or "Franklin stood back of me in everything I wanted to do" (Eleanor Roosevelt, quoted by Catherine Drinker Bowen, Atlantic Monthly, March 1970). The first term, dating from the late 1600s, was long criticized as an undesirable colloquialism but today is generally considered acceptable. The variants, at the back of, from about 1400, and in back of, from the early 1900s, also can be used both literally and figuratively and could be substituted for back of in either example. Also see BACK OF BEYOND.
American Heritage Idioms