alpine fir: medium-tall timber tree of the Rocky Mountains having a narrowly conic to columnar crown
silver fir: any of various true firs having leaves white or silvery white beneath
volt: a unit of potential equal to the potential difference between two points on a conductor carrying a current of 1 ampere when the power dissipated between the two points is 1 watt; equivalent to the potential difference across a resistance of 1 ohm when 1 ampere of current flows through it