ochre vs yellow ochre

ochre and yellow ochre both are nouns.

Word	Noun	Adjective	Verb	Adverb
ochre	Yes	Yes	No	No
yellow ochre	Yes	No	No	No

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

ochre: any of various earths containing silica and alumina and ferric oxide; used as a pigment
yellow ochre: pigment consisting of a limonite mixed with clay and silica

Other hyponyms of ochre include sinoper, sinopia, sinopis, yellow ocher.

ochre (noun)	yellow ochre (noun)
a moderate yellow-orange to orange color	pigment consisting of a limonite mixed with clay and silica
any of various earths containing silica and alumina and ferric oxide; used as a pigment

ochre (adjective)	yellow ochre (adjective)
of a moderate orange-yellow color