—n. 1. the bottom support of anything; that on which a thing stands or rests: a metal base for the table. 2. a fundamental principle or groundwork; foundation; basis: the base of needed reforms. 3. the bottom layer or coating, as of makeup or paint.
4. Archit. a. the distinctively treated portion of a column or pier below the shaft or shafts. See diag. under column. b. the distinctively treated lowermost portion of any construction, as a monument, exterior wall, etc.
5. Bot.,Zool. a. the part of an organ nearest its point of attachment.
b. the point of attachment.
6. the principal element or ingredient of anything, considered as its fundamental part: face cream with a lanolin base; paint with a lead base. 7. that from which a commencement, as of action or reckoning, is made; a starting point or point of departure.
8. Baseball. a. any of the four corners of the diamond, esp. first, second, or third base. Cf. home plate. b. a square canvas sack containing sawdust or some other light material, for marking first, second, or third base.
9. a starting line or point for runners, racing cars, etc.
10. (in hockey and other games) the goal.
11. Mil. a. a fortified or more or less protected area or place from which the operations of an army or an air force proceed.
b. a supply installation for a large military force.
12. Geom.the line or surface forming the part of a figure that is most nearly horizontal or on which it is supposed to stand.
13. Math. a. the number that serves as a starting point for a logarithmic or other numerical system.
b. a collection of subsets of a topological space having the property that every open set in the given topology can be written as the union of sets of the collection.
c. a collection of neighborhoods of a point such that every neighborhood of the point contains one from the collection.
d. a collection of sets of a given filter such that every set in the filter is contained in some set in the collection.
14. Also called base line.Survey.See under triangulation (def. 1).
15. Painting. a. vehicle (def. 10).
b. Also calledcarrier. inert matter, used in the preparation of lakes, onto which a coloring compound is precipitated.
16. Photog.a thin, flexible layer of cellulose triacetate or similar material that holds the light-sensitive film emulsion and other coatings, esp. on motion-picture film.
17. Chem. a. a compound that reacts with an acid to form a salt, as ammonia, calcium hydroxide, or certain nitrogen-containing organic compounds.
b. the hydroxide of a metal or of an electropositive element or group.
c. a group or molecule that takes up or accepts protons.
d. a molecule or ion containing an atom with a free pair of electrons that can be donated to an acid; an electron-pair donor.
e. any of the purine and pyrimidine compounds found in nucleic acids: the purines adenine and guanine and the pyrimidines cytosine, thymine, and uracil.
18. Gram.the part of a complex word, consisting of one or more morphemes, to which derivational or inflectional affixes may be added, as want in unwanted or biolog- in biological. Cf. root1 (def. 11), stem1 (def. 16).
19. Ling.the component of a generative grammar containing the lexicon and phrase-structure rules that generate the deep structure of sentences.
20. Electronics. a. an electrode or terminal on a transistor other than the emitter or collector electrodes or terminals.
b. the part of an incandescent lamp or electron tube that includes the terminals for making electrical connection to a circuit or power supply.
21. Stock Exchange.the level at which a security ceases a decline in price.
22. Heraldry.the lower part of an escutcheon.
23. bases,Armor.a tonlet formed of two shaped steel plates assembled side by side.
24. Jewelry.pavilion (def. 6).
25. get to first base. See first base (def. 2).
26. in base,Heraldry.in the lower part of an escutcheon.
27. off base, a. Baseball.not touching a base: The pitcher caught him off base and, after a quick throw, he was put out by the second baseman. b. Informal.badly mistaken: The police were way off base when they tried to accuse her of the theft. 28. on base,Baseball.having reached a base or bases: Two men are on base. 29. touch base with, to make contact with: They've touched base with every political group on campus.
—adj. serving as or forming a base: The walls will need a base coat and two finishing coats.
—v.t. 1. to make or form a base or foundation for.
2. to establish, as a fact or conclusion (usually fol. by on or upon): He based his assumption of her guilt on the fact that she had no alibi. 3. to place or establish on a base or basis; ground; found (usually fol. by on or upon): Our plan is based on a rising economy. 4. to station, place, or situate (usually fol. by at or on): He is based at Fort Benning. The squadron is based on a carrier.
—v.i. 1. to have a basis; be based (usually fol. by on or upon): Fluctuating prices usually base on a fickle public's demand. 2. to have or maintain a base: I believe they had based on Greenland at one time.
—adj. 1. morally low; without estimable personal qualities; dishonorable; meanspirited; selfish; cowardly.
2. of little or no value; worthless: hastily composed of base materials. 3. debased or counterfeit: an attempt to eliminate the base coinage. 4. characteristic of or befitting an inferior person or thing.
5. of illegitimate birth.
6. not classical or refined: base language. 7. Old Eng. Law.held by tenure less than freehold in return for a service viewed as somewhat demeaning to the tenant.
8. Archaic. a. of humble origin or station.
b. of small height.
c. low in place, position, or degree: base servitude. 9. Obs.deep or grave in sound; bass: the base tones of a piano.