merino sheep vs domestic sheep

merino sheep and domestic sheep both are nouns.

Word	Noun	Adjective	Verb	Adverb
merino sheep	Yes	No	No	No
domestic sheep	Yes	No	No	No

As nouns, domestic sheep is a hypernym of merino sheep; that is, domestic sheep is a word with a broader meaning than merino sheep:

merino sheep: white sheep originating in Spain and producing a heavy fleece of exceptional quality
domestic sheep: any of various breeds raised for wool or edible meat or skin

Other hypernyms of merino sheep include Ovis aries.

merino sheep (noun)	domestic sheep (noun)
white sheep originating in Spain and producing a heavy fleece of exceptional quality	any of various breeds raised for wool or edible meat or skin