BASE

n. & v. --n. 1 a a part that supports from beneath or serves as a foundation for an object or structure. b a notional structure or entity on which something draws or depends (power base). 2 a principle or starting-point; a basis. 3 esp. Mil. a place from which an operation or activity is directed. 4 a a main or important ingredient of a mixture. b a substance, e.g. water, in combination with which pigment forms paint etc. 5 a substance used as a foundation for make-up. 6 Chem. a substance capable of combining with an acid to form a salt and water and usu. producing hydroxide ions when dissolved in water. 7 Math. a number in terms of which other numbers or logarithms are expressed (see RADIX). 8 Archit. the part of a column between the shaft and pedestal or pavement. 9 Geom. a line or surface on which a figure is regarded as standing. 10 Surveying a known line used as a geometrical base for trigonometry. 11 Electronics the middle part of a transistor separating the emitter from the collector. 12 Linguistics a root or stem as the origin of a word or a derivative. 13 Baseball etc. one of the four stations that must be reached in turn when scoring a run. 14 Bot. & Zool. the end at which an organ is attached to the trunk. 15 Heraldry the lowest part of a shield. --v.tr. 1 (usu. foll. by on, upon) found or establish (a theory based on speculation; his opinion was soundly based). 2 (foll. by at, in, etc.) station (troops were based in Malta). øbase hospital esp. Austral. a hospital in a rural area, or (in warfare) removed from the field of action. base pairing Biochem. complementary binding by means of hydrogen bonds of a purine to a pyrimidine base in opposite strands of nucleic acids. base rate Brit. the interest rate set by the Bank of England, used as the basis for other banks' rates. base unit a unit that is defined arbitrarily and not by combinations of other units. [F base or L basis stepping f. Gk]