primer >> /ˈpraɪmər/
Definition: [noun] 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.
Example: apply three coats of primer
Definition: [noun] A cap or cylinder containing a compound which responds to friction or an electrical impulse and ignites the charge in a cartridge or explosive.
Example: the nitro-cellulose is ignited by the spark that comes from the primer
Definition: [noun] A small pump for pumping fuel to prime an internal combustion engine, especially in an aircraft.
Example: no more than four pumps of the primer usually suffice
Definition: [noun] A molecule that serves as a starting material for a polymerization process.
Example: the duplex RNA primer cannot initiate DNA replication