consent

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

• intransitive verb To give assent, as to the proposal of another; agree: synonym: assent.
• intransitive verb Archaic To be of the same mind or opinion.
• noun Acceptance or approval of what is planned or done by another; acquiescence. synonym: permission.
• noun Agreement as to opinion or a course of action.

from The Century Dictionary.

• noun Voluntary allowance or acceptance of what is done or proposed to be done by another; a yielding of the mind or will to that which is proposed; acquiescence; concurrence; compliance; permission.
• noun In law, intelligent concurrence in the adoption of a contract or an agreement of such a nature as to bind the party consenting; agreement upon the same thing in the same sense.
• noun Agreement in opinion or sentiment; unity of opinion or inclination.
• noun A preconcerted design; concert.
• noun Agreement; correspondence in parts, qualities, or operation; harmony; concord.
• noun In pathology, an agreement or sympathy, by which one affected part of the system affects some distant part. See sympathy.
• noun Synonyms Assent, Consent, Concurrence, etc. See assent.
• To agree in sentiment; be of the same mind; accord; be at one.
• To agree; yield credence or accord; give assent, as to a proposition or the terms of an agreement.
• To yield when one has the right, power, or desire to oppose; accede, as to persuasion or entreaty; aid, or at least voluntarily refrain from opposing, the execution of another person's purpose; comply.
• Synonyms See list under accede. Permit, Consent to, etc. See allow.
• To grant; allow; acknowledge; give assent to.

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

• intransitive verb To agree in opinion or sentiment; to be of the same mind; to accord; to concur.
• intransitive verb To indicate or express a willingness; to yield to guidance, persuasion, or necessity; to give assent or approval; to comply.
• noun Agreement in opinion or sentiment; the being of one mind; accord.
• noun Correspondence in parts, qualities, or operations; agreement; harmony; coherence.
• noun Voluntary accordance with, or concurrence in, what is done or proposed by another; acquiescence; compliance; approval; permission.
• noun (Law) Capable, deliberate, and voluntary assent or agreement to, or concurrence in, some act or purpose, implying physical and mental power and free action.
• noun (Physiol.) Sympathy. See Sympathy, 4.
• noun (Law) an age, fixed by statute and varying in different jurisdictions, at which one is competent to give consent. Sexual intercourse with a female child under the age of consent is punishable as rape.
• transitive verb obsolete To grant; to allow; to assent to; to admit.

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

• verb intransitive To express willingness, to give permission.
• verb transitive, medicine To cause to sign a consent form.
• noun Voluntary agreement or permission

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

• noun permission to do something
• verb give an affirmative reply to; respond favorably to