n. A tree of the genus Acer, including about fifty species. Acer saccharinum is the rock maple, or sugar maple, from the sap of which sugar is made, in the United States, in great quantities, by evaporation; the red maple or swamp maple is Acer rubrum; the silver maple, Acer dasycarpum, having fruit wooly when young; the striped maple, Acer Pennsylvanium, called also moosewood. The common maple of Europe is Acer campestre, the sycamore maple is Acer Pseudo-platanus, and the Norway maple is Acer platanoides.