blade vs backsword

blade and backsword both are nouns.

Word	Noun	Adjective	Verb	Adverb
blade	Yes	No	No	No
backsword	Yes	No	No	No

As nouns, backsword is a hyponym of blade; that is, backsword is a word with a more specific, narrower meaning than blade:

blade: a cutting or thrusting weapon that has a long metal blade and a hilt with a hand guard
backsword: a sword with only one cutting edge

Other hyponyms of blade include broadsword, cavalry sword, saber, sabre, cutlas, cutlass, falchion, fencing sword, rapier, tuck.

blade (noun)	backsword (noun)
the flat part of a tool or weapon that (usually) has a cutting edge	a sword with only one cutting edge
a cutting or thrusting weapon that has a long metal blade and a hilt with a hand guard	a stick used instead of a sword for fencing
flat surface that rotates and pushes against air or water
the part of the skate that slides on the ice
a broad flat body part (as of the shoulder or tongue)
a cut of beef from the shoulder blade
something long and thin resembling a blade of grass
a dashing young man
especially a leaf of grass or the broad portion of a leaf as distinct from the petiole