• (a.) Relating to derivation.
a term used in morphology to refer to one of the two main processes of work-formation, the other being inflectional . Derivational processes result in words of a different class. In English, the major derivational process is suffixation, e.g. derive - derivation, happy - happiness, nation - national.
Der`i·va'tion·al adjective Relating to derivation. Earle. 
[adj] - characterized by inflections indicating a semantic relation between a word and its base
adjective characterized by inflections indicating a semantic relation between a word and its base; `the morphological relation between `sing` and `singer` and `song` is derivational`