"delay," late 14c., from O.Fr. differer, from L. differre "set apart, put off, delay," also "be different, differ," from dis- "apart" + ferre "carry" (see infer). Etymologically identical with differ; the spelling and pronunciation differentiated from 15c., partly by association of this word with delay.
"yield," late 15c., from M.Fr. deferer, from L. deferre "carry away, transfer, grant;" modern sense is from meaning "refer (a matter) to someone," from de- "down, away" + ferre "carry" (see infer).