1560s, from residue + -al (1), or from French résiduel, from Latin residuum.
residual (n.)
1550s, in mathematics, from residual (adj.) or from residue + -al (2). Residuals "royalties" attested by 1960.
he could retire on his residuals
residual quantity
reside
residence
residency
resident
residential
residual
residue
resign
re-sign
resignation
resigned
