Ross Hassig discusses the macuahuitl/macana; calls it a "sword"; notes that the Spanish called it a "sword" and that they described it as able to decapitate a horse in combat.
Ross Hassig, Aztec Warfare: Imperial Expansion and Political Control (Norman, Oklahoma: University of Oklahoma Press, 1988), 83, 85
The Aztec swords (macuahuitl), which Spaniards quickly labeled with the Taino word macana, seem to have been of at least two varieties—one-handed and two-handed (see figs. 4, 5, 7, 11, 13, 31-33). These were made of wood, usually oak, 76 to 102 millimeters (3-4 inches) wide and a little over a meter (3.5 feet) long. They have obsidian or flint blades fitted and glued into grooves along the edge. Drawings indicate rectangular, ovoid, and pointed designs.
The adhesive employed varied, with both bitumen and “turtle during glue” being cited for the task. Some swords had thongs through which the user could put his hand to secure the weapon in battle. The two-handed variety is described as being about four inches wide and as tall as a man. Macuahuitl wielders are regularly depicted with the sword in one hand and a shield in the other, but using a two-handed sword obviously precludes that.
The macuahuitl is bladed on both sides and can be used in a powerful downward slash, but it can also inflict a sharp backhand cut. One of the persistent observations of the conquistadors was the ability of these swords to cut the head from a horse with a single blow. Furthermore the Aztec swords were described by the conquistadors as cutting better than the Spanish swords and being so cleverly constructed that the blades could be neither pulled out nor broken.
There is no known surviving example of the macuahuitl. However, there are numerous illustrations in various sixteenth-century drawings, and, as with the lance, one example did survive in the Real Armería in Madrid until it was destroyed in 1884. A print remains, but it is also mislabeled (see fig. 10). As with the thrusting spear, the stone blades of the macuahuitl in the print are closely set, forming a virtually continuous cutting edge. Other drawings indicate that they were sometimes discontinuous, forming a gapped, possibly serrated, edge. I can find no depictions of the typical Aztec carvings at Chichen Itza, however, single warriors are holding clubs with two separated blades protruding form each side, these may have been early variants of the macuahuitl. Another example comes from a mural form the eight-century Maya site of Bonampak, in which one warrior is wielding a club with blades on one side and a single point or blade on the other.