Wordnet 3.0
NOUN (1)
1. 
 a baby conceived by fertilization that occurs outside the mother's body; 
 the woman's ova are removed and mixed with sperm in a culture medium - if fertilization occurs the blastocyte is implanted in the woman's uterus; 
WordNet (r) 3.0 (2006):
test-tube baby
    n 1: a baby conceived by fertilization that occurs outside the
         mother's body; the woman's ova are removed and mixed with
         sperm in a culture medium - if fertilization occurs the
         blastocyte is implanted in the woman's uterus