mass noun
1- a substance used as a preparatory coat on previously unpainted wood, metal, or canvas, especially to prevent the absorption of subsequent layers of paint or the development of rust底层涂料, 底漆。
1.1
- a cap or cylinder containing a compound which responds to friction or an electrical impulse and ignites the charge in a cartridge or explosive火帽, 底火; 点火药。
1.2
- a small pump for pumping fuel to prime an internal-combustion engine, especially in an aircraft（尤指飞机内燃发动机的）启动注油泵。
1.3
- Biochemistry a molecule that serves as a starting material for a polymerization process【生化】引物, 引子。