[Philip]

In a European context, the yanyuedao / yem nguyet dao could be classified as a fauchard rather than a glaive, by virtue of the projecting prong or spike halfway up the spine. In some catalogs the term glaive is applied to weapons having a smoothly concave spine; the Japanese naginata is a close equivalent.

Some scholars, like Arturo Puricelli-Guerra, do simplify things by just calling both types "glaives" although he does state that the "true" glaive has its point in-line with the axis of the shaft, and acknowledges that in centuries past the term falco / falcione (hence, fauchard) was also current.

For those curious about the parallel development of these knife-like polearms in the Western world, I recommend his well-illustrated article "The Glaive and the Bill" in ART, ARMS, AND ARMOUR (ed. Robert Held, 1979). In Europe the fauchard morphed by the 17th cent. into a magnificent but unwieldy piece of ceremonial regalia for the bodyguards of patrician families, unlike the halberd and partizane which retained a nominal battlefield role into the following century.