In linguistics, clipping is the word formation process which consists in the reduction of a word to one of its parts (Marchand: 1969). Clipping is also known as "truncation" or "shortening."
According to Marchand (1969), clippings are not coined as words belonging to the standard vocabulary of a language. They originate as terms of a special group like schools, army, police, the medical profession, etc., in the intimacy of a milieu where a hint is sufficient to indicate the whole. For example, exam(ination), math(ematics), and lab(oratory) originated in school slang; spec(ulation) and tick(et = credit) in stock-exchange slang; and vet(eran) and cap(tain) in army slang. Clipped forms can pass into common usage when they are widely useful, becoming part of standard English, which most speakers would agree has happened with math/maths, lab, exam, phone (from telephone), fridge (from refrigerator), and various others. When their usefulness is limited to narrower contexts, such as with tick in stock-exchange slang, they remain outside standard register. Many, such as mani and pedi for manicure and pedicure or mic/mike for microphone, occupy a middle ground in which their appropriate register is a subjective judgment, but succeeding decades tend to see them become more widely used.
Clipping is different from back-formation – back-formation may change the part of speech or the word's meaning, whereas clipping creates shortened words from longer words, but does not change the part of speech or the meaning of the word.
According to Irina Arnold (1986), clipping mainly consists of the following types:
Final (or back) clipping is the most common type, in which the beginning of the prototype is retained. The unclipped original may be either a simple or a composite. Examples are: ad (advertisement), cable (cablegram), doc (doctor), exam (examination), fax (facsimile), gas (gasoline), gym (gymnastics, gymnasium), memo (memorandum), mutt (muttonhead), pub (public house), pop (popular music).
Initial (or fore) clipping retains the final part of the prototype. Examples: bot (robot), chute (parachute), roach (cockroach), coon (raccoon), gator (alligator), phone (telephone), pike (turnpike), varsity (university), net (Internet).