base

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The lowest or bottom part.
• noun The part of a plant or animal organ that is nearest to its point of attachment.
• noun The point of attachment of such an organ.
• noun A supporting part or layer; a foundation.
• noun A basic or underlying element; infrastructure.
• noun The fundamental principle or underlying concept of a system or theory; a basis.
• noun A fundamental ingredient; a chief constituent.
• noun The fact, observation, or premise from which a reasoning process is begun.
• noun Games A starting point, safety area, or goal.
• noun Baseball Any one of the four corners of an infield, marked by a bag or plate, that must be touched by a runner before a run can be scored.
• noun A center of organization, supply, or activity; a headquarters.
• noun The portion of a social organization, especially a political party, consisting of the most dedicated or motivated members.
• noun A fortified center of operations.
• noun A supply center for a large force of military personnel.
• noun A facial cosmetic used to even out the complexion or provide a surface for other makeup; a foundation.
• noun Architecture The lowest part of a structure, such as a wall, considered as a separate unit.
• noun Heraldry The lower part of a shield.
• noun Linguistics A morpheme or morphemes regarded as a form to which affixes or other bases may be added.
• noun The side or face of a geometric figure to which an altitude is or is thought to be drawn.
• noun The number that is raised to various powers to generate the principal counting units of a number system. The base of the decimal system, for example, is 10.
• noun The number raised to the logarithm of a designated number in order to produce that designated number; the number at which a chosen logarithmic scale has the value 1.
• noun A line used as a reference for measurement or computations.
• noun Any of a class of compounds whose aqueous solutions are characterized by a bitter taste, a slippery feel, the ability to turn litmus blue, and the ability to react with acids to form salts.
• noun A substance that yields hydroxide ions when dissolved in water.
• noun A substance that can act as a proton acceptor.
• noun A substance that can donate a pair of electrons to form a covalent bond.
• noun The region in a transistor between the emitter and the collector.
• noun The electrode attached to this region.
• noun One of the nitrogen-containing purines (adenine and guanine) or pyrimidines (cytosine, thymine, and uracil) that occurs attached to the sugar component of DNA or RNA.
• adjective Forming or serving as a base.
• adjective Situated at or near the base or bottom.
• adjective Chemistry Of, relating to, or containing a base.
• transitive verb To form or provide a base for.
• transitive verb To find a basis for; establish.
• transitive verb To assign to a base; station.
• idiom (off base) Badly mistaken.
• adjective Having or showing a lack of decency; contemptible, mean-spirited, or selfish.
• adjective Being a metal that is of little value.
• adjective Containing such metals.
• adjective Archaic Of low birth, rank, or position.
• adjective Obsolete Short in stature.