aft—Behind; toward the after or stern part of a vessel. Thus, the poop deck is aft.
alee—To put the helm alee means to bring it toward the side of the ship away from the wind. This heads the boat into the wind, or, if the helm is kept alee, brings her about.
aloft—Up in the tops—overhead. In the upper rigging, or on the yards, etc.
alongside—By the side of.
amidships—Generally speaking, the middle portion of a vessel.
anchor—A metal hook specially designed to take hold of the bottom in comparatively shallow water. A cable connecting the anchor and the ship makes it possible for a ship to maintain her position against wind or tide or current. Anchors are of many shapes and vary in size from a few pounds to a number of tons.
anchorage—A section of a harbour or a roadstead where ships may anchor.
aneroid—A barometer which is operated by the pressure of the atmosphere on a metal disc covering a partial vacuum. The varying pressure operates the hand on a dial, and this is graduated to the same scale as is a mercurial barometer.
artemon—A sail used on Roman ships. It was square and was mounted at the bow on a kind of mast that leaned over the bow. Later its place was taken by the spritsail.
astern—Behind. In the after part of the vessel; behind the vessel; in her wake.