The Collaborative International Dictionary of English v.0.48:

Quay \Quay\, n. [F. quai. See Key quay.]
   A mole, bank, or wharf, formed toward the sea, or at the side
   of a harbor, river, or other navigable water, for convenience
   in loading and unloading vessels. [Written also key.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Quay \Quay\, v. t.
   To furnish with quays.
   [1913 Webster]

WordNet (r) 3.0 (2006):

quay
    n 1: wharf usually built parallel to the shoreline