Merriam-Webster's Collegiate® Dictionary, 11th Edition
YACHT
I. noun
Etymology: obsolete Dutch jaght, from Middle Low German jacht, short for jachtschip, literally, hunting ship
Date: 1557
any of various recreational watercraft: as, a sailboat used for racing, a large usually motor-driven craft used for pleasure cruising,
II. intransitive verb
Date: 1836
to race or cruise in a yacht