Ok Hal, trying not to get in over my head here! Was hoping you were going to take it and run with it!
I tried going back and finding where that terminology came from, with no luck.
Bladelet, utilized as a knife or tool driven from core, apparently without the intentions of being hafted or made into a bi-face form. I think the larger (longer) ones were made in the earliest times and the smaller (shorter) ones were from a later period.
The one I posted is right at 3in's, the info above is just my understanding and should not be considered to hold much credibility !!!!