term limit

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A provision, as in a state constitution or city charter, that restricts the number of terms an elected or appointed official may serve.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A legal restriction that limits the number of terms a person may serve in a particular elected office.
• noun The maximum number of terms one may legally serve in a particular elected office.
• verb transitive, informal Alternative spelling of term-limit.