1ke, of course, is correct. However, as I’ve moved about the US through the years, it also seems that the terms are sometimes used interchangeably, depending upon the region of the country in which one resides.
More often it is a Protestant baptism of an infant that is regularly called a “Christening.”
Catholics almost always, and correctly, use the term Baptism for our sacrament. But I’ve heard “Christening” used in casual conversation, often as a general term in reference to the celebration being hosted following the sacrament, rather than the sacrament itself.