Word family
A word family is the base form of a word plus its inflected forms and derived forms made with suffixes and prefixes plus its cognates, i.e. all words that have a common etymological origin, some of which even native speakers don't recognize as being related (e.g. "wrought (iron)" and "work(ed)"). In the English language, inflectional affixes include third person -s, verbal -ed and -ing, plural -s, possessive -s, comparative -er and superlative -est. Derivational affixes include -able, -er, -ish, -less, -ly, -ness, -th, -y, non-, un-, -al, -ation, -ess, -ful, -ism, -ist, -ity, -ize/-ise, -ment, in-.