To baptize something or someone is to perform the ceremony of baptism. This baptism has varied meanings and procedures depending on the organization performing it. In Christian churches a baptism can give a person a name, make him or her a member of the congregation, or cleanse him or her of sin (or sometimes all three of these things). The word is sometimes pronounced with a b sound, especially in the Southern United States.
Baptise is the preferred spelling outside North America; as well as: baptised and baptising. For North America the standard is baptize, baptizing, baptized.
However, baptism is used everywhere.
Examples in North America:
On Sunday, the Romano family was on the brink of a new life – they had moved to Burlington from Winnipeg and were on their way to Argentina to baptize their 15-month-old son Lucca. [Toronto Star]
Baldwin was baptized into the LDS Church in May, just one week after her 100th birthday. [Deseret News]
A beach baptism ceremony hosted by Christ Journey Church was held at Bill Baggs Cape Florida State Park on Key Biscayne on Saturday, July 26, 2014. [Miami Herald]