From the archaic noun ܐܲܦܹܐ (appē, “surface, face”) + -ܝܬܐ (-āytā, the feminine adjectival ending).
ܐܲܦܵܝܬܵܐ • (appāytā) f (plural ܐܲܦܵܝ̈ܵܬ݂ܵܐ (appāyāṯā))