Yacht is a singular noun. You are unclear about the meaning of "what noun is it". You need to ask more clearly what you are looking for.
A fleet of yachts
Yacht is a noun beginning with Y, yell is a verb, and young is an adjective.
· yacht · yak · yam · yard · yardstick · yarn · yo-yo · yogurt · yoke
yacht
Christensen Yacht Company
Robert yacht
inventor yacht
Yacht is German
yes a yacht is a ship.
The plural of yacht is yachts.
A yacht with an open cockpit.
Yacht