In my reading to try to learn about the disk layout, directory, and boot process of TRS-80 Model I and Model III, I see some unusual words come up again and again.
Along with the common terms "track" and "sector" there are also the unusual words "granule" and "lump".
My guess is that one of these must be Tandy's dialect for "block". But which? And then what could the other possibly mean?