(môr′tər) noun
1. A strong bowl–like vessel in which substances are crushed or pounded with a pestle.
2. Mil. A piece of ordnance with a large bore for firing heavy shells at low muzzle velocity and great angles of elevation that they may drop upon the object aimed at.
3. Mining A tublike cast–iron receptacle with grated sides, in which ore is stamped.
4. Any of several devices for hurling pyrotechnic shells or bombs and also life lines. [OE mortere <L mortarium]

(môr′tər) noun
1. A building material prepared by mixing lime, plaster of Paris, or cement, with sand, water, and sometimes other materials. It is used in masonry, plastering, etc.
2. Loosely, a cement.
—v.t. To plaster or join with mortar. [<OF mortier <L mortarium]