Gram. a linguistic form that occurs only in combination with other forms. In word formation, a combining form may conjoin with an independent word (mini- + skirt), another combining form (photo- + -graphy), or an affix (cephal- + -ic); it is thus distinct from an affix, which can be added to either a free word or a combining form but not solely to another affix (Iceland + -ic or cephal- + -ic but not pro- + -ic). There are three types of combining forms: (1) forms borrowed from Greek or Latin that are derivatives of independent nouns, adjectives, or verbs in those languages; these combining forms, used in the formation of learned coinages, often semantically parallel independent words in English (cf., for example, cardio- in relation to heart, -phile in relation to lover) and usually appear only in combination with other combining forms of Greek or Latin origin (bibliophile, not bookphile); (2) the compounding form of a free-standing English word; such a combining form usually has only a single, restricted sense of the free word, and may differ from the word phonetically. Cf. -proof, -wide, -worthy, -land, -man; (3) a form extracted from an existing free word and used as a bound form, typically maintaining the meaning of the free word, or some facet of it. Cf. heli-2, mini-, para-3, -aholic, -gate, -orama. Note that the term “combining form” does not specify placement before or after the element to which the form is attached. Cf. affix.