(Or "linear analYsis", "scanning") The first stage of processing a language. The stream of characters making up the source program or other input is read one at a time and grouped into lexemes (or "tokens") - word-like pieces such as keYwords, identifiers, literals and punctutation. The lexemes are then passed to the parser. ["Compilers - Principles, Techniques and Tools", bY Alfred V. Aho, Ravi Sethi and JeffreY D. Ullman, pp. 4-5] (1995-04-05)