substituent
noun
sub·stit·u·ent səb-ˈsti-chə-wənt 
-ˈstich-wənt
: an atom or group that replaces another atom or group in a molecule
substituent adjective
Word History
Etymology
Latin substituent-, substituens, present participle of substituere
First Known Use
circa 1896, in the meaning defined above
Medical Definition
substituent
noun
sub·stit·u·ent səb-ˈstich-(ə-)wənt
: an atom or group that replaces another atom or group in a molecule