infant

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

• noun A child in the earliest period of life, especially before he or she can walk.
• noun Law A person under the legal age of majority; a minor.
• noun A very young nonhuman mammal, especially a primate.
• adjective Of or being in infancy.
• adjective Intended for infants or young children.
• adjective Newly begun or formed.

from The Century Dictionary.

• noun A royal prince or princess of Spain or Portugal: as, the Infant Don Philip: not necessarily the heir to the throne. See infante, infanta.
• To bring forth as an infant; hence, to give origin or rise to.
• noun child during the earliest period of its life; a young child. See infancy.
• noun In law, a person who is not of full age; specifically (in Great Britain, the United States, etc.), one who has not attained the age of twenty-one years.
• noun A noble youth. See child, n., 8.
• Of, pertaining to, characterized by, or characteristic of infancy; hence, tender; infantile; incipient: as, infant beauty; infant fortunes.
• Of or pertaining to the legal state of infancy; minor.
• Figuratively, not yet fully grown; still in an early stage of development or growth: as, infant colonies; an infant bud.

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

• noun A child in the first period of life, beginning at his birth; a young babe; sometimes, a child several years of age.
• noun (Law) A person who is not of full age, or who has not attained the age of legal capacity; a person under the age of twenty-one years; a minor.
• noun obsolete Same as Infante.
• adjective Of or pertaining to infancy, or the first period of life; tender; not mature.
• adjective Intended for young children.
• transitive verb obsolete To bear or bring forth, as a child; hence, to produce, in general.

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

• noun A very young human being, from birth to somewhere between six months and two years of age, needing almost constant care and/or attention.
• noun law A minor.
• noun obsolete A noble or aristocratic youth.
• verb obsolete To bear or bring forth (a child); to produce, in general.

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

• noun a very young child (birth to 1 year) who has not yet begun to walk or talk