plough vs ard

plough and ard both are nouns.

Word	Noun	Adjective	Verb	Adverb
plough	Yes	No	Yes	No
ard	Yes	No	No	No

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

plough: a farm tool having one or more heavy blades to break the soil and cut a furrow prior to sowing
ard: a simple light plough without a mouldboard.

Other hyponyms of plough include bull tongue, moldboard plow, mouldboard plough, ard plough, scratch plough.

plough (noun)	ard (noun)
a farm tool having one or more heavy blades to break the soil and cut a furrow prior to sowing	a simple light plough without a mouldboard.

plough (verb)	ard (verb)
to break and turn over earth especially with a plow
move in a way resembling that of a plow cutting into or going through the soil