ziggurat vs zikkurat

ziggurat and zikkurat both are nouns.

Word	Noun	Adjective	Verb	Adverb
ziggurat	Yes	No	No	No
zikkurat	Yes	No	No	No

As nouns, ziggurat and zikkurat are synonyms defined as:

ziggurat and zikkurat: a rectangular tiered temple or terraced mound erected by the ancient Assyrians and Babylonians

Other synonyms of ziggurat include zikurat.

ziggurat (noun)	zikkurat (noun)
a rectangular tiered temple or terraced mound erected by the ancient Assyrians and Babylonians	a rectangular tiered temple or terraced mound erected by the ancient Assyrians and Babylonians