Webster's 1828 Dictionary
COMBINING
ppr. Uniting closely; joining in purpose; confederating; uniting by chimical affinity.
New American Oxford Dictionary
combining form
com bin ing form |kəmˈbīniNG kəmˈbaɪnɪŋ fɔrm | ▶noun Grammar a linguistic element used in combination with another element to form a word (e.g., Anglo- ‘English ’ in Anglo-American, bio- ‘life ’ in biology, -graphy ‘writing ’ in biography ). usage: In this dictionary, combining form is used to denote an element that contributes to the particular sense of words (as with bio- and -graphy in biography ), as distinct from a prefix or suffix that adjusts the sense of or determines the function of words (as with un-, -able, and -ation ).
Oxford Dictionary
combining form
com |bin ¦ing form ▶noun Grammar a form of a word normally used in compounds in combination with another element to form a word (e.g. Anglo- ‘English ’ in Anglo-Irish, bio- ‘life ’ in biology, -graphy ‘writing ’ in biography ). usage: In this dictionary, combining form is used to denote an element that contributes to the particular sense of words (as with bio- and -graphy in biography ), as distinct from a prefix or suffix that adjusts the sense of or determines the function of words (as with un-, -able, and -ation ).