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. Compare 
-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. Compare 
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.