constituent

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

• adjective Serving as part of a whole; component.
• adjective Empowered to elect or designate.
• adjective Authorized to make or amend a constitution.
• noun A constituent part; a component. synonym: element.
• noun A resident of a district or member of a group represented by an elected official.
• noun One that authorizes another to act as a representative; a client.
• noun A structural unit, such as a verb, noun phrase, or clause, in a grammatical construction.

from The Century Dictionary.

• Constituting or existing as a necessary component or ingredient; forming or composing as a necessary part; component; elementary: as, oxygen and hydrogen are the constituent parts of water.
• Having the power of constituting or appointing, or of electing to public office: as, a constituent body.
• noun One who or that which constitutes or forms, or establishes or determines.
• noun That which constitutes or composes as a part, or a necessary part; a formative element or ingredient.
• noun One who constitutes another his agent; one who empowers another to transact business for him, or appoints another to an office in which the person appointed represents him as his agent.
• noun One who elects or assists in electing another to a public office; more generally, any inhabitant of the district represented by an elective officer, especially by one elected to a legislative body: so called with reference to such officer.

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

• noun The person or thing which constitutes, determines, or constructs.
• noun That which constitutes or composes, as a part, or an essential part; a component; an element.
• noun One for whom another acts; especially, one who is represented by another in a legislative assembly; -- correlative to representative.
• noun (Law) A person who appoints another to act for him as attorney in fact.
• adjective Serving to form, compose, or make up; elemental; component.
• adjective Having the power of electing or appointing.

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

• adjective being a part, or component of a whole
• adjective authorized to make a constitution
• noun a part, or component of a whole
• noun The person or thing which constitutes, determines, or constructs.
• noun A resident of a place represented by an elected official.
• noun law One who appoints another to act for him as attorney in fact.
• noun grammar A functional element of a phrase or clause.

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

• noun (grammar) a word or phrase or clause forming part of a larger grammatical construction
• noun an artifact that is one of the individual parts of which a composite entity is made up; especially a part that can be separated from or attached to a system
• noun something determined in relation to something that includes it
• noun a member of a constituency; a citizen who is represented in a government by officials for whom he or she votes
• adjective constitutional in the structure of something (especially your physical makeup)
• noun an abstract part of something