Here's why that is:
* The letter "p" is just the starting point: You can add any number of other letters to form a word.
* Words can be very long: Think of "pneumonoultramicroscopicsilicovolcanoconiosis" - a real, but very long word!
Do you want to explore some specific "p" words? If you tell me a topic or category (like animals, places, or feelings) I can give you a list!