chemo-

1.
a combining form with the meanings “chemical,” “chemically induced,” “chemistry,” used in the formation of compound words:
chemotherapy.
Also, especially before elements of Latin origin, chemi-.
Also, especially before a vowel, chem-.
Origin
chem-, extracted from chemical or chemistry + -o- or -i-
British Dictionary definitions for chemo-

chemo-

combining form
1.
indicating that chemicals or chemical reactions are involved: chemotherapy
Word Origin
New Latin, from Late Greek khēmeia; see alchemy
Word Origin and History for chemo-

before vowels chem-, word-forming element denoting "relation to chemical action or chemicals," from comb. form of chemical (adj.), used to form scientific compound words from c.1900.

chemo- in Medicine

chemo- or chemi- or chem-
pref.
Chemicals; chemical: chemotherapy.