a triangular prism with an apex angle slightly less than 180°: when illuminated by a point source of light it produces two overlapping beams that form an interference pattern on a screen.
Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 6 Various
a prism having a highly obtuse angle to facilitate beam splitting
a missile or rocket propellant, composed of fuel and oxidizer, the components of which are kept in separate compartments prior to combustion. noun a rocket propellant consisting of two substances, usually a fuel and an oxidizer Also called dipropellant Compare monopropellant
bips billion instruction per second
a form symmetrical about a plane dividing it into two pyramids. noun a geometrical form consisting of two pyramids with a common polygonal base
the fourth power. noun (maths) the fourth power