dock, port
prow
sail
A quay is a platform built parallel to the shore where ships can tie up to. A pier is another four letter word where a ship can dock.
hut
Hut
Sanctuary
arbor
A four letter word starting with the letter a is able.
arbor
den
It is of French origin meaning 'a place to shelter a car'. Derives from the word 'garer' meaning to shelter and also dock ships. Garage came into use about 1902
It depends on what you mean by 'four letter word'. Thea has four letters, so yes it is. It is not a swear word, so it's not that kind of 'four letter word'.