Originally Posted by inBOIL

The H in Jesus H. Christ stands for haploid.

Originally Posted by Cecil Adams

It recalls the H in the IHS logo emblazoned on much Christian paraphernalia. IHS dates from the earliest years of Christianity, being an abbreviation of "Jesus" in classical Greek characters. The Greek pronunciation is "Iesous," with the E sound being represented by the character eta, which looks like an H. When the symbol passed to Christian Romans, for whom an H was an H, the unaccountable character eventually became accepted as Jesus's middle initial.