PWF & SEM ???

[Zapster]

I have an automated pipe library that list PVC fittings with connection types being PWF & SEM. The PWF fittings look and are dimensioned like a SW (socket weld) and the SEM connection type is like a plain spigot end. My guess would be PWF Pocket Weld Female ????? SEM Spigot End Male ???? Really I have no idea. Can someone help resolve the acronym question?

Thanks