a tree of the genus acer, including about fifty species. a. 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 or swamp maple is a. rubrum; the silver maple, a. dasycarpum, having fruit wooly when young; the striped maple, a. pennsylvanium, called also moosewood. the common maple of europe is a. campestre, the sycamore maple is a. pseudo-platanus, and the norway maple is a. platanoides.