"Plaustral" Natural Recordings by Native Speakers
Blunder. The word "plaustral" is not a real word. However, the word "plastron" is related, and it is probably what you were thinking of. A plastron is the area of a turtle's belly, or the rear half of the under shell of a turtle. It is also an alternative term for a nondescript or misleading idea or statement. Brown's used the term to describe Ben Franklin's writings, describing them as vague.