derivationally

Derivationally is an adverb used in linguistics to indicate that something relates to derivation, the process of forming a new word from a base form by affixation or other modification that typically changes meaning or category. The word is formed from the adjective derivational with the suffix -ly. In scholarly discussions, derivationally contrasts with inflectional processes, which modify a word’s grammatical function without creating a new lexical item.

In morphology, derivation differs from inflection in that it often yields new words and can change the word class. For example, adding suffixes or prefixes to a base can produce nouns, adjectives, or verbs from a single root. A common illustration is forming happiness from happy by adding -ness, a derivational process; likewise, teach can yield teacher through a derivational suffix that shifts the word’s part of speech. Derivationally focused descriptions emphasize how such word-formation steps build new vocabulary rather than merely adjusting tense, number, or case.

Derivationally appears mainly in technical writing and linguistic analysis, where precise discussion of word formation is required. It helps analysts specify that the discussion concerns the method of deriving new words, not merely modifying existing ones through agreement or tense. The term ultimately derives from the verb derive, through the noun derivation and the adjective derivational, with its adverbial suffix -ly.

See also: Derivation (linguistics), Morphology, Derivational morphology, Affixation.