6 Statements [stmt.stmt]

6.3 Compound statement or block [stmt.block]

1

So that several statements can be used where one is expected, the compound statement (also, and equivalently, called “block”) is provided.

compound-statement:
    { statement-seqopt }
statement-seq:
    statement
    statement-seq statement

A compound statement defines a block scope ([basic.scope]). [ Note: A declaration is a statement ([stmt.dcl]).  — end note ]