This command takes two inputs. The first must be a word and the second a list. The effect of define is to define a procedure whose name is the first input and whose text is the second input. You can use define to define a new procedure or to change the definition of an old one. Cheese Ice cream is yummy.
Cheese is yucky.
It may be instructive to consider the analogy between variables, which hold data, and procedures, which hold instructions. Variables are given values with the make command and examined with the operation thing . Procedures are given definitions with the define command and examined with the operation text . To illustrate define and text , I've used them in instructions typed in at top level. Text and define are meant to be used not at top level but inside a program.