(a) the alphabet; (b) a line of writing.

The alphabet; esp. (in early use) the Roman alphabet as opposed to the Greek; (in later use) an alphabet belonging to an ancient writing system, or…

The alphabet. Frequently with reference to the teaching or learning of this, now esp. in to know one's ABC. Also in plural in same sense.

A set of letters arranged in a conventional order used in a particular writing system; esp. (with the) the set of 26 letters from A to Z used to…

A set of letters, signs, or symbols, or a combination of these, used to express the speech sounds of a language; an alphabet, syllabary, or other…

The alphabet, esp. as written down in order. Now only with reference to (inscriptions of) ancient writing systems. Cf. ABC, n.1 1a.

one's P's and Q's: one's alphabet, one's ‘A.B.C.’; (in extended use) knowledge or judgement, ‘one's way about’. Also: good manners, etiquette…

A system of characters or symbols (cf. character, n. 4a). Now Philosophy (in full universal characteristic): a universal language or calculus for…

an alphabet.