"pertaining to an agent or to an agency," 1847, from Medieval Latin agentia (see agency) + -al (1). Related: Agentially.
Entries linking to agential
agency n.
1650s, "active operation;" 1670s, "a mode of exerting power or producing effect," from Medieval Latin agentia, abstract noun from Latin agentem (nominative agens) "effective, powerful," present participle of agere "to set in motion, drive forward; to do, perform," figuratively "incite to action; keep in movement" (from PIE root *ag- "to drive, draw out or forth, move"). The meaning "establishment where business is done for another" is recorded by 1861.
-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)).