8. (Fort.) The exterior side of the polygon, or that imaginary line which connects the salient angles of two adjacent bastions.
9. (Geom.) The line or surface constituting that part of a figure on which it is supposed to stand.
10. (Math.) The number from which a mathematical table is constructed; as, the base of a system of logarithms.
11. [See Base low.] A low, or deep, sound. (Mus.) (a) The lowest part; the deepest male voice. (b) One who sings, or the instrument which plays, base. [Now commonly written bass.]
The trebles squeak for fear, the bases roar.
Dryden.
12. (Mil.) A place or tract of country, protected by fortifications, or by natural advantages, from which the operations of an army proceed, forward movements are made, supplies are furnished, etc.