infant /in″fənt/ [L, infans, unable to speak] , 1. n., a child who is in the earliest stage of extrauterine life, a time extending from the first month after birth to approximately 12 months of age, when the baby is able to assume an erect posture. 2. n., (in law) a person not of full legal age; a minor. 3. adj., pertaining to infancy; in an early stage of development. −infantile, adj.
