St. Patfrisk -- the Patron Saint of Boston Irish Cops?

I just came across the term "patfrisk," which seems to be almost exclusively a Massachusettsism, though the "pat frisk" (or "pat-frisk") version also appears with some frequency in New York and Minnesota.  The first reference to "patfrisk" is in 1995 and to "pat frisk" in 1969, but without any self-consciousness, so it makes me think that it had been in the air before.

Patfrisk appears to be defined as a "carefully limited search of the outer clothing of [a] person[] … to discover weapons" (authorized by the Court in Terry v. Ohio). The term is likely a frisk × patdown portmanteau, but it's not clear to me how it differs from just a frisk. I crave enlightenment, if there is some subtle distinction.