small-for-gestational-age infant(n = noun.person) sga infant - an infant whose size and weight are considerably less than the average for babies of the same age;
is a kind of neonate, newborn, newborn baby, newborn infant

abandoned infant, infant, infant death, infant deathrate, infant feeding, infant mortality, infant mortality rate, infant prodigy, infant school, liveborn infant, low-birth-weight infant, newborn infant, postmature infant, premature infant, preterm infant, sga infant, stillborn infant, sudden infant death syndrome, term infant