So, a glaive is a polearm. It’s a chunk of wood with a long blade on the end, sort of like a warscythe, bardiche or billhook. It normally has one edge on the blade, though a blade on the reverse side isn’t unheard of (though that may technically be a different polearm, I’m not certain.)
The triple blade polearms are all descended from the Spetum. These were all (or almost all) bladed spears, with two protruding (sometimes sharpened) tines, called wings to prevent migration up the blade. I think the Ranseur is an example, where the wings were sharpened.
That said, the spetum and it’s descendants were in the “poke it until it stops squirming and screaming” family of polearms, the glaive was in the “whack it a couple times” family. So, I’m not sure what you’re looking for.