IPA: /ˈpaɪp.fʊl/
KK: /ˈpaɪpˌfʊl/
The quantity of tobacco or other material that can be contained in a pipe.
He packed the pipe with a full pipeful of tobacco before lighting it.
Pipeful → It is formed from "pipe" (from Old English "pīpe", meaning a tubular object for conveying liquids or gases) and "-ful" (meaning full of). The word "pipeful" means the amount that a pipe can hold or is full of.
Think of a 'pipe' that is 'full' of something — that's what a 'pipeful' refers to.