A number that is raised to a power, or base of an exponential function. This finds common use, for example, in the depiction of numbers, for instance, 10 is the base used in the decimal system, whereas 2 is the base in the binary system. See also Numeral system.
Table of bases -- A table of the values of 1-100 in bases 2-20.
In chemistry, a base is the reactive complement to an acid. (Sometimes the term alkali has been used historically where base is now preferred.) See Acid-base reaction theories. Technically, a substance capable of neutralizing acid, with a pH greater than 7.0.
In biochemistry, see nitrogenous base.
In baseball, a base is one of 4 bags placed at corners of the infield diamond that a player has to run to after hitting the ball.