Is it ensure, insure, or assure?
1820, "pertaining to mental conception" (there is an isolated use from 1662), from Medieval Latin conceptualis, from Latin conceptus "a collecting, gathering, conceiving," past participle of concipere (see conceive). Related: Conceptualism; conceptualist.
conceptual con·cep·tu·al (kən-sěp'chōō-əl)
Relating to concepts or the the formation of concepts.