"scientific study of fish, ichthyology," 1857, a jocular hybrid from Latin piscatus, past participle of piscari "to fish," from pisces "a fish" (from PIE root *pisk- "a fish") + -ology.
pirogi
pirogue
pirouette
pis aller
Pisa
piscatology
piscatorial
piscatory
Pisces
piscine
piscivorous