ETYM Latin expressio: cf. French expression.
In music, signs or words providing a dramatic context for the interpretation of neutral performance indicators for tempo, dynamics, phrasing, and so on.
1. Expression without words; SYN. manifestation, reflection, reflexion.
2. The communication (in speech or writing) of one's beliefs or opinions.
3. The expression on a person's face; SYN. look, aspect, facial expression, face.

A combination of symbols—identifiers, values, and operators—that yields a result upon evaluation. The resulting value can then be assigned to a variable, passed as an argument, tested in a control statement, or used in another expression.