<computer programming> Any piece of program code in a high-level language which, when (if) its execution terminates, returns a value. In most programming languages, expressions consist of constants, variables, operators, functions, and parentheses. The operators and functions may be built-in or user defined. Languages differ on how expressions of different types may be combined - with some combination of explicit casts and implicit coercions.

The syntax of expressions generally follows conventional mathematical notation, though some languages such as Lisp or Forth have their own idiosyncratic syntax.

(01 Jun 2001)

<molecular biology> The process by which a gene's coded information is converted into the structures present and operating in the cell.

Expressed genes include those that are transcribed into mRNA and then translated into protein and those that are transcribed into RNA but not translated into protein (for example, transfer and ribosomal RNAs).

(06 Aug 1998)