1610s, "dominion of a caliph," from caliph + -ate (1). The meaning "rank of a caliph" is recorded from 1753.
Entries linking to caliphate
caliph n.
late 14c., "ruler of a Muslim country," from Old French caliphe (12c., also algalife), from Medieval Latin califa, from Arabic khalifa "successor" (from khalafa "succeed"). The title given to the successor of Muhammad as leader of the community and defender of the faith; the first was Abu-Bakr, who succeeded Muhammad in the role of leader of the faithful after the prophet's death.
-ate 1
word-forming element used in forming nouns from Latin words ending in -atus, -atum (such as estate, primate, senate). Those that came to English via French often arrived with -at, but an -e was added after c. 1400 to indicate the long vowel. The suffix also can mark adjectives formed from Latin past participles in -atus, -ata (such as desolate, moderate, separate); again, they often were adopted in Middle English as -at, with an -e appended after c. 1400.