Relating to or characteristic of an administrator or administration; having the nature of administrative functions.
From administer + -ial suffix. Derived from Latin ministrare (to serve), with the -ial ending creating an adjective. This term describes things pertaining to the administrative or management functions.
This adjective is almost never used anymore—we'd just say 'administrative'—but it shows how English had lots of competing word forms, and only some of them survived into modern usage while others got left behind.
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