scalar
n.n. a single number that represents a physical quantity, like temperature or speed. It is different from a vector, which has both a size and a direction.
n. a physical quantity that has magnitude but no direction. In mathematics and physics, it is a single-valued quantity that can be represented by a real or complex number.
The temperature is a scalar quantity.
In the physics lab, students measured the scalar value of the room's temperature and the vector direction of the wind.
While the velocity of the object is a vector, the speed at which it moves is a scalar, representing only the magnitude of the motion.
Borrowed from Latin scālāris, adjectival form from scāla (“a flight of steps, stairs, staircase, ladder, scale”), for *scadla, from scandere (“to climb”); compare scale. The mathematics sense was coined by Irish mathematician and astronomer William Rowan Hamilton in 1846.