alphabet

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The letters of a language, arranged in the order fixed by custom.
2. n. A system of characters or symbols representing sounds or things.
3. n. A set of basic parts or elements: "genetic markers . . . that contain repeated sequences of the DNA alphabet” ( Sandra Blakeslee).

Century Dictionary and Cyclopedia

1. n. The letters of a language arranged in the customary order; the series of letters or characters which form the elements of written language. See the articles on the different letters, A, B, C, etc.
2. n. Any series of characters intended to be used in writing instead of the usual letters, as the series of dashes, dots, etc., used in the transmission of telegraphic messages.
3. n. First elements; simplest rudiments: as, not to know the alphabet of a science.
4. To arrange in the order of an alphabet; mark by the letters of the alphabet.

Wiktionary

1. n. The set of letters used when writing in a language.
2. n. A typically finite set of distinguishable symbols.
3. n. One particular letter used in writing a language.

GNU Webster's 1913

1. n. The letters of a language arranged in the customary order; the series of letters or signs which form the elements of written language.
2. n. The simplest rudiments; elements.
3. v. To designate by the letters of the alphabet; to arrange alphabetically.

WordNet 3.0

1. n. the elementary stages of any subject (usually plural)
2. n. a character set that includes letters and is used to write a language