What does "lex" mean?

1. (computing/programming) to turn a stream of text into small pieces called tokens so a computer can understand it. 2. (short name) a short, friendly name for people called Alexander or Alexandra.

How do you use "lex"?

Usually used as a transitive verb in the context of compiler design.

lex

v. · n.

US //ˈɫɛks// lex

1 computing/programming (v.)
C2 Proficiency Technical Computing

to turn a stream of text into small pieces called tokens so a computer can understand it.

to perform lexical analysis on a character stream, converting it into a sequence of tokens for a parser.

Example

The compiler needs to lex the source code before it can check for errors.

Example

The program failed because it could not correctly lex the unconventional symbols used in the input file.

Usage

Usually used as a transitive verb in the context of compiler design.
- tokenize
- parse
2 short name (n.)
B2 Upper Intermediate Informal

a short, friendly name for people called Alexander or Alexandra.

a hypocoristic or pet form of given names such as Alexander, Alexandra, or Alexis.

Example

Everyone at the office calls him Lex instead of Alexander.

Example

Lex was chosen as a gender-neutral nickname that suited her preference for brevity over the more traditional Alexandra.
- alex

Etymology 1

From lexical analysis, from lexical.

Etymology 2

Latin lex (“law”).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

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Last updated June 20, 2026