Illustrated glossaries
Glossaries in print and online
Booklet
Recording Timber-framed Buildings: an Illustrated Glossary
Council for British Archaeology, 1996. An essential little book, the cornerstone of timber-framed vernacular architecture terminology. Someone should do an app of this. Unfortunately there is no single handy booklet equivalent for masonry.
Leaflet
An illustrated Glossary for the BARD tick-box building summary - a PDF of a very handy concise 6-page guide. It's free.
Online
The Surrey Domestic Buildings Research Group website has an illustrated glossary of terms. Awkward to navigate but some good illustrations, and covers brick and stonework.
The Vernacular Architecture Group also has an online illustrated glossary based on the Practical Handbook Recording Timber-Framed Buildings: an Illustrated Glossary by Nat Alcock, Maurice Barley, Philip Dixon and Bob Meeson.
App
Pevsner's Architectural Glossary is an excellent app (£3.99) for tablets and smartphones, based on the Pevsner hardback book which defines and illustrates general architectural terms. But it touches only slightly on vernacular terms. Perfect if you're in a church or a great house though.