in·fan·cy/`ɪnfənsɪ; ˈɪnfənsi/ n [U] 1 the period in a child's life before he or she can walk or talk 婴儿期: Their son died in infancy. 他们的儿子在婴儿时期就死了。 2 in its infancy something that is in its infancy is just starting to be developed 在初期［开始］阶段: In the 1930s air travel was still in its infancy. 20 世纪 30 年代时航空旅行才刚刚起步。