In SQL, which of the following is not a data definition language commands?

In SQL, the Data Definition Language (DDL) is used to define, manage, and modify the structure of a database. DDL commands are primarily responsible for creating, altering, or deleting tables, schemas, and other database objects. Among the options provided:

Option C: UPDATE is not a data definition language command. UPDATE is a Data Manipulation Language (DML) command used to modify data within existing tables, not to define or manage the structure of the database.

The other options, REVOKE, RENAME, and GRANT, are DDL commands used for managing user privileges, renaming database objects, and controlling access, respectively.
So, the correct answer is Option C: UPDATE.