-mer

Chemistry
1.
a combining form meaning “member of a particular group”:
isomer.
Compare -mere, -merous.
Origin
< Greek méros part, portion
British Dictionary definitions for -mer

-mer

suffix
1.
(chem) denoting a substance of a particular class: monomer, polymer
Word Origin
from Greek meros part
-mer in Medicine

-mer suff.
Variant of -mere.

-mer in Science
-mere or -mer  
A suffix meaning "part" or "segment," as in blastomere, one of the cells that form a blastula.