Affix

An affix is a morpheme that is attached to a word stem to form a new word.

Types

Affixes may be derivational or inflectional.

• Inflectional affixes assign grammatical properties (such as number, gender, tense, person) to the stem in order to form the different word forms of the same lexeme ("-s" in "tables", "-ed" in "loved")
• Derivational affixes form a new lexeme by modifying the meaning (and sometimes the category) of the root ("un-" in "unhappy", "-ness" in "happiness").

Position

Affixes are divided depending on their position with reference to the stem

• prefix (PFX) - Appears at the front of the stem (such as "un-" in "undo", or "re-" in "rewrite")
• suffix (SFX) - Appears at the back of the stem (such "-s" in "tables", or "-er" in "writer")
• infix (IFX) - Appears within the stem (very rare in English, such as "-ma-" in "sophistimacated")
• circumfix (CCX) - Appears at the front and at the back of the stem (very rare in English, such as "a-" + "-ed" in "ascattered")