MySQL enum vs. set

As the MySQL documentation states:

Definition of a ENUM or SET column does act as a constraint on values entered into the column. An error occurs for values that do not satisfy these conditions:

An ENUM value must be one of those listed in the column definition, or the internal numeric equivalent thereof. The value cannot be the error value (that is, 0 or the empty string). For a column defined as ENUM('a','b','c'), values such as '', 'd', or 'ax' are illegal and are rejected.

A SET value must be the empty string or a value consisting only of the values listed in the column definition separated by commas. For a column defined as SET('a','b','c'), values such as 'd' or 'a,b,c,d' are illegal and are rejected.

analogy:
ENUM = radio fields (only accepted values are those listed, may only choose one)
SET = checkbox fields (only accepted values are those listed, may choose multiple)