#Old Church Slavonic

• Az — A polysemantic term with widespread structural application; it represents the name of the first letter in the Old Church Slavonic Cyrillic alphabet (also meaning the personal pronoun 'I'). In a contemporary international context, it functions as the standardized two-letter ISO country code for Azerbaijan and as the top-level domain extension (.az) for web pages registered in this region, suggesting a clear and clean geographical localization.
• Primer — An old popular archaism, regional variant, or nominal locution historically used in the Romanian language to designate the primer, the old Cyrillic alphabet, or the first elementary notions of learning. The term was structurally formed by merging the names of the first two letters of the Slavo-Cyrillic alphabet, 'az' (A) and 'buche' (B), preserving a deep cultural connotation linked to the beginnings of schooling and early literacy efforts in traditional communities.
• Cyrillic primer — An archaic elementary textbook used in the past within monastic and church schools of the Romanian principalities for learning the Cyrillic alphabet and mastering reading in Slavonic or Romanian; an ancient primer. This educational text gathered within a simple structure traditional letters, basic prayers, and scriptural fragments, serving as a fundamental pillar in the delicate process of early literacy and primary education before modern textbooks emerged.