Just received an 18kt gold Cyma watch and matching bracelet, the deployment clasp say several things, 750, Swiss made, cyma, some hallmarks, and 18KTS Gold. What does 18kts gold Mean. Is it solid 18kt? Thanks

Not sure what you mean by "solid". 18kt. is a gold alloy. Pure gold is 24kt.
18kt is a common alloy for jewelry.

I mean is 18kts the same as 18k or 18kt, solid 18 karat gold? Thanks

Are you sure it is an "s" , not an "f". F means gold filled, much less valuable than 18kt.

750 means it's 75% gold the other 25% is an alloy. 18kt means that the 75% that is gold, is 18 karat gold.