ard plough vs plough

ard plough and plough both are nouns.

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

As nouns, plough is a hypernym of ard plough; that is, plough is a word with a broader meaning than ard plough:

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

Other hypernyms of ard plough include plow.

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

ard plough (verb)	plough (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