baptism       
noun [ C or U ]  religion uk/ˈbæp.tɪ.zəm/ us/ˈbæp.tɪ.zəm/
 (基督教的)洗礼,浸礼
a Christian ceremony in which a person has water poured on their head, or is covered for a very short time in water, in order to show that that person has become a member of the Christian Church
  infant baptism 婴儿洗礼 
 Idiom   
a baptism of/by fireidiom  初次的痛苦经历;火的洗礼
a very difficult first experience of something
  I was given a million-dollar project to manage in my first month - it was a real baptism of fire. 第一个月就让我管理一个百万美元的项目——这可是个严峻的考验。