conditional statement: A statement that controls the flow of execution depending on some condition.
condition: The boolean expression in a conditional statement that determines which branch runs.
boolean expression: An expression whose value is either True or False.
relational operator: One of the operators that compares its operands, such as ==, !=, >, <, >=, and <=.
logical operator: One of the operators that combines boolean expressions: and, or, and not.
compound statement: A statement that consists of a header and a body. The header ends with a colon :. The body is indented relative to the header.
branch: One of the alternative sequences of statements in a conditional statement.
chained conditional: A conditional statement with a series of alternative branches.
nested conditional: A conditional statement that appears in one of the branches of another conditional statement.