What is the X in X-mas?
early 14c., originally in legal sense of "to call" to a higher judge or court, from Anglo-French apeler "to call upon, accuse," Old French apeler "make an appeal" (11c., Modern French appeler), from Latin appellare "to accost, address, appeal to, summon, name," iterative of appellere "to prepare," from ad- "to" (see ad-) + pellere "to beat, drive" (see pulse (n.1)). Related: Appealed; appealing.
Probably a Roman metaphoric extension of a nautical term for "driving a ship toward a particular landing." Popular modern meaning "to be attractive or pleasing" is quite recent, attested from 1907 (appealing in this sense is from 1891), from the notion of "to address oneself in expectation of a sympathetic response."
c.1300, in the legal sense, from Old French apel (Modern French appel), back-formation from apeler (see appeal (v.)). Meaning "call to an authority" is from 1620s; that of "attractive power" attested by 1916.
a reference of any case from an inferior to a superior court. Moses established in the wilderness a series of judicatories such that appeals could be made from a lower to a higher (Ex. 18:13-26.) Under the Roman law the most remarkable case of appeal is that of Paul from the tribunal of Festus at Caesarea to that of the emperor at Rome (Acts 25:11, 12, 21, 25). Paul availed himself of the privilege of a Roman citizen in this matter.