A floe is similar to a field, but smaller, inasmuch as its extent can be seen.
Glacier. A mass of ice derived from the atmosphere, sometimes abutting on the sea.
Heavy and light are terms attached to ice, distinguishable of its thickness.
A hummock is a protuberance raised upon any plane of ice above the common level. It is frequently produced by pressure, where one piece is squeezed upon another, often set upon its edge, and in that position cemented by the frost. Hummocks are likewise formed by pieces of ice mutually crushing each other, the wreck being heaped upon one or both of them. To hummocks, principally, the ice is indebted for its variety of fanciful shapes and its picturesque appearance. They occur in great numbers in heavy packs, on the edges, and occasionally in the middle of fields and floes, where they often attain the height of thirty feet and upwards.
Ice-belt. A continued margin of ice, which, in high northern latitudes, adheres to the coast above the ordinary level of the sea.
Iceberg. A large mass of solid ice, generally of great height, breadth, and thickness.
Ice-foot. Ice attached to the land, either in floes or in heavy grounded masses lying near the shore.
Ice-hook. A small ice-anchor.
A lane or vein is a narrow channel of water in packs or other collections of ice.
A lead is an opening, large or small, through the ice, in which a vessel can be able to make some progress either by sailing, tracking, or towing.