plough vs bull tongue

plough and bull tongue both are nouns.

Word	Noun	Adjective	Verb	Adverb
plough	Yes	No	Yes	No
bull tongue	Yes	No	No	No

As nouns, bull tongue is a hyponym of plough; that is, bull tongue 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
bull tongue: a heavy plow with a single wide blade; used chiefly in cotton fields

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

plough (noun)	bull tongue (noun)
a farm tool having one or more heavy blades to break the soil and cut a furrow prior to sowing	a heavy plow with a single wide blade; used chiefly in cotton fields

plough (verb)	bull tongue (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