In basic English usage, an
infant is defined as a human child at the youngest stage of life, specifically before they can walk and generally before the age of one (see also
child and
adolescent).
The term "infant" derives from the
Latin word
in-fans, meaning "unable to speak." There is no exact definition for infancy. "Infant" is also a legal term with the meaning of
minor; that is, any child under the age of legal adulthood.
A human infant less than a month old is a
newborn infant or a
neonate. The term "newborn" includes
premature infants, postmature infants and
full term newborns.