IPA: /ˌdɛfɪˈnɪʃənl/
KK: /dɪˈfɪnɪʃənl/
Relating to the meaning or explanation of a word or concept.
The definitional aspects of the term were discussed in the meeting.
Definitional → It is formed from "definire" (from Latin, meaning to limit or determine) and the suffix "-al" (meaning pertaining to). The word "definitional" refers to something that pertains to the act of defining or determining the meaning of something.
Think of the act of 'limiting' or 'determining' a meaning ('definire') — that's why 'definitional' relates to defining something.