Referring to a quantity that has a magnitude or numerical value, in contrast to a vector, which also has direction. Thus, mass, speed, and temperature are scalar quantities, unlike velocity and force, which are vector quantities.
Statistics
A number. The term is often used to distinguish a number from a vector or matrix.
Computer
A number comprising a single value (such as an integer or real number), as opposed to a complex number (containing two scalars) or a vector (which is a scalar only in the special case of its containing one number).
Geography
In GIS, scalar data are defined by measurements based on a common standard. A particular data set may use a measurement system that may only apply to itself. ‘GIS allows you to establish a scalar description for features you can’t really measure any other way’ (M. N. DeMers 2009) as in a ranking of landscapes by beauty.