synthesis vs synthesise

synthesis is a noun but synthesise is not a noun.

Word	Noun	Adjective	Verb	Adverb
synthesis	Yes	No	No	No
synthesise	No	No	Yes	No

synthesis (noun)	synthesise (noun)
the combination of ideas into a complex whole
reasoning from the general to the particular (or from cause to effect)
the process of producing a chemical compound (usually by the union of simpler chemical compounds)

synthesis (verb)	synthesise (verb)
	combine so as to form a more complex, product