"pertaining to behavior," 1927, in psychology, from behavior + -al (1).
Entries linking to behavioral
behavior n.
"manner of behaving (whether good or bad), conduct, manners," late 15c., essentially from behave, but with ending from Middle English havour "possession," a word altered (by influence of have) from aver, noun use of Old French verb aveir "to have."
-al 1
suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).
behavioural adj.
chiefly British English spelling of behavioral (q.v.); for spelling, see -or.