[doodad]

A pip is another name for a lemon seed.

[SAJ]

Any fruit seed, actually. Consider "The Five Orange Pips", one of Conan Doyle's Sherlock Holmes tales.

More common usage in the UK than in the US, of course.

[RobinOfKingston]

A pip is another name for a lemon seed.

A 'pip' is also an extraordinary thing, e.g., "Ain't that a pip?"

[Gondring]

It was actually the nickname of Gladys Knight's cousin. I'm not certain why that nickname. Perhaps a reference to Pip of Great Expectations or Moby Dick, if not fruit seeds, dice spots, or military insignia?

[gogogodzilla]

Or a pomegranate one...