chr = christened (generally taken to be same as baptism but this is the actual pouring of water while chistening is I think the acceptance of the child into the church by giving he/she a name and providing sponsors (the god-parents)
As effectively few civil records of births exist on the Island before 1877 most records will show the baptism(bp)/Christening(chr) at the parish church - the Manx generally kept to the old Catholic custom that christening took place within a few days of birth (but this is not guaranteed!)