(bās) noun
1. The lowest or supporting part of anything; bottom; foundation.
2. Ling. The form of a word used in making derivatives, as by adding prefixes or suffixes; root or stem.
3. A determining ingredient; a common element with which other more distinctive elements unite to form a product; essential or preponderant element or part of anything.
4. Chem. a A compound which is capable of so uniting with an acid as to neutralize its acid properties and form a salt, as sodium hydroxide, NaOH. b A compound that yields hydroxyl ions in solution. c Any molecule or radical that takes up protons.
5. A basis of military or naval operations or of supplies.
6. In baseball, any one of the four points of the diamond; also, in certain other games, or in a race, the goal or starting point.
7. Any point, part, line, number, or quantity from which a reckoning, inference, or conclusion proceeds, or on which any other dimension depends; any principle or datum; a basis: the base of an argument, the base of a triangle.
8. A very accurately measured line on the earth's surface, from whose known length other lines in a survey are determined.
9. A number on which a mathematical system or calculation depends: In the Arabic notation, 10 is the base of the decimal system.
10. Geom. a That side of a rectilineal figure or that face of a solid on which the figure is conceived to be erected. b A side or face which has some special mark or character, or to which other parts are referred.
11. Biol. The end opposite to the apex; the point of attachment.
12. Archit. The lowest member of a structure, as the basement of a building, the plinth (when present) and base moldings of a column, or the lowest course of a wall; a pedestal.
13. The celluloid component of a motion-picture film.
14. Her. The lower part of the shield.
—off base
1. In baseball, not on the base one should be on.
2. Colloq. Utterly wrong about something.
—v.t. based, bas·ing
1. To place or ground on a logical basis, as an argument, decision, or theory: with on or upon.
2. To make or form a base for.
—adjective
1. Serving as a base: a base line.
2. Situated at or near the base: a base angle. ◆ Homophone: bass². [<F <L basis <Gk. basis step, pedestal <bainein go]

(bās) adjective
1. Low in sentiment, morals, or rank.
2. Low in value.
3. Alloyed, debased, or counterfeit, as money; not silver or gold: base metals.
4. Music Bass.
5. In English law, held by villeinage: opposed to free: said of a tenure of an estate.
6. Obs. Of humble or ignoble birth; also, illegitimate.
7. Menial; servile.
8. Not classical: said of languages. ◆ Homophone: bass². [<OF bas <LL bassus low]
—base′ly adverb
—base′ness noun Synonyms: abject, beggarly, cheap, contemptible, cringing, degraded, degrading, despicable, groveling, ignoble, infamous, low, low-minded, mean, mean-spirited, menial, miserable, obsequious, paltry, poor, poor-spirited, scurvy, servile, shabby, slavish, sneaking, sordid, squalid, subservient, vile, worthless, wretched. Antonyms: arrogant, conceited, dignified, eminent, esteemed, exalted, haughty, honorable, illustrious, independent, insolent, lofty, noble, pompous, princely, proud, self-assertive, self-conceited, self-reliant, self-respectful, supercilious, superior, supreme, vain, worthy.