Now couldn't it be called a glaive tho🤔
Glaives are more similar to Japanese naginata than an axe, though generally they have a broader blade than a naginata. Also, technically the name refers to being "sword on a stick" in essence XD
A glaive's blade is affixed to the shaft via a socket style, so in that respect it is similar to an axe - but its usage is more similar to other long polearms like a halberd (which specifically has a rear spike / hammer head, a top spike, and an axe head), Chinese guandao, Japanese naginata, etc.
Looking at Lindwurm in Chapter 4.2, page 9 again - that is most definitely a type of axe, and I would like to call it a poleaxe, though it does not have a well-defined head spike at the top like most poleaxes, or a rear counterweight / spike. It does, however, have a very well-defined head built for chopping. So if we're going by purely technical definition, it'd be more like a Dane axe or something similar - a very long-shafted axe designed for use with two hands.
But I'm still going to call it a poleaxe because it reminds me of the one I own, lol.