basic

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

• adjective Of, relating to, or forming a base; fundamental.
• adjective Of, being, or serving as a starting point or basis.
• adjective Of or relating to a base.
• adjective Containing a base, especially in excess of acid.
• adjective Alkaline.
• adjective Geology Containing little silica, as certain igneous rocks.
• noun An essential, fundamental element or entity.
• noun Basic training.

from The Century Dictionary.

• Relating to a base; of the nature of a base; fundamental.
• In chem.: Performing the office of a base in a salt. Having the base in excess; having more than one equivalent of the base for each equivalent of acid.
• In geology, containing a relatively small amount of silica: applied to crystalline rocks, as basalt: opposed to acidic.
• In anatomy, basal; basilar.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Computers) an artificial computer language with a relatively simplified instruction set.
• adjective Relating to a base; performing the office of a base in a salt.
• adjective Having the base in excess, or the amount of the base atomically greater than that of the acid, or exceeding in proportion that of the related neutral salt.
• adjective Apparently alkaline, as certain normal salts which exhibit alkaline reactions with test paper.
• adjective (Min.) Said of crystalline rocks which contain a relatively low percentage of silica, as basalt.
• adjective (Chem.) a salt formed from a base or hydroxide by the partial replacement of its hydrogen by a negative or acid element or radical.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective necessary, essential for life or some process.
• adjective elementary, simple, fundamental, merely functional.
• adjective chemistry Of or pertaining to a base; antonym of acidic
• noun A necessary commodity, a staple requirement.
• noun An elementary building block, e.g. a fundamental piece of knowledge.
• noun military basic training.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective reduced to the simplest and most significant form possible without loss of generality
• adjective serving as a base or starting point
• adjective pertaining to or constituting a base or basis
• adjective of or denoting or of the nature of or containing a base
• noun (usually plural) a necessary commodity for which demand is constant
• noun a popular programming language that is relatively easy to learn; an acronym for beginner's all-purpose symbolic instruction code; no longer in general use