Most piping threads are produced to national or industry group standards describing threads form - threads angle, pitch and diameter. Common standards are
In general pitch refers to threads per inch for fractional screw threads and pipe threads. For metric screw threads pitch refers to the distance between threads.
Common piping thread standards in the United States are
Other common piping thread standards
Tapered threads are for joining and sealing and straight threads are only for joining.
More about piping thread standards.