Warren in Lancaster, PA
I well remember the first time I heard the term "chip breaker". I visited a fellow who was a collector and plane expert around 1981. When he said " the name chip breaker is a misnomer because it's really just a blade stiffener", I almost fell over. I was so shocked I did not know what to say. He went on to demonstrate how his wonderful plane gave a rather poor surface. I had abandoned single iron planes, high angle planes, scrapers, and sand paper some years before.

I think the term "chip breaker" was historically used for both a machinist's lathe tool and for part of a planing machine. I think it a poor term because we use the word shaving (not chip) to denote the discharge from planes, and we have for hundred of years. I prefer the terms cap iron or top iron.

The term double iron plane has been used here in Pennsylvania at least since 1767. I think I have seen references using this term from every decade since that time.