Tokenize

Tokenizing is the operation of replacing one set of symbols with another, typically to make the resulting set of symbols smaller.

The term is most commonly used in computers, where a programming language source code, a set of symbols in an english-like format, is converted into another format that is much smaller. Most BASIC interpreters used this to save room, a command such as print would be replaced by a single number which uses much less room in memory. In fact most lossless compression systems use a form of tokenizing, although it's typically not referred to as such.