Well, honey, the fruit that starts with a P and ends with an M is a plum. But let me tell you, if you're looking for a fruit that starts with a P and ends with an M, you might need to brush up on your alphabet skills, darling.
An orange fruit that begins with P is papaya.
Pumpkin is the fruit you are looking for. It contains 7 letters and begins with the letter P.
atop
pizzazz.
Pies
pill
PEA
pawpaw
pill pencil
envelope
Emperor shrimp
Peachpeach