If you're traveling by sea in almost any part of the world which has an abundance of small islands packed closely together, you will probably encounter the romantic word "caique", either with or without the umlaut (pair of dots) over the "i", caïque. They are commonly used in the Greek Islands.
Not A Kayak!
Don't confuse a caique with a kayak - they are two entirely different kinds of boats.
Turkish in origin, a caique is a small boat, generally narrow and made of wood, and usually powered by an engine though it may have sails as well and some can be rowed.
It's the workhorse of the islands, often being used for multiple purposes of fishing, tourist or family transport, and the shipment of goods. Being small, they can easily slide into small harbors and draw close enough to many beaches so that passengers can either dart down a gangplank onto the sand or can wade onto shore. Remote nude beaches on Mykonos are often reached by caique.
Many boats loosely referred to as "caiques" may actually be small yachts or other vessels, just tossed in under the caique category as a convenience, indicating a small boat which can get close to the beaches.
In rougher water, sensitive stomachs will definitely know that they are on a boat on most caiques, but in practice, caique captains watch the very accurate Greek weather reports carefully and any warnings tend to be carefully heeded. Still, a packet of Dramamine doesn't take up much room, just in case.
Caiques can rarely be booked online or far ahead - they tend to be something that you find by walking the harbor and seeing boats with chalkboard schedules by their gangplanks.