Robert K. Barnhart (1933 – April 2007) was an American lexicographer and editor of various specialized dictionaries.
[1] With his father and Sol Steinmetz, he edited the three volumes of The Barnhart Dictionary of New English (1973, 1980, 1990).
Perhaps his major work is The Barnhart Dictionary of Etymology (1988), which is marketed under the title Chambers Dictionary of Etymology in the United Kingdom.
He edited an abridgement, The Barnhart Concise Dictionary of Etymology (1995).
Robert's brother David K. Barnhart is also a lexicographer.