yellow ochre vs yellow ocher

yellow ochre and yellow ocher both are nouns.

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

As nouns, yellow ochre and yellow ocher are synonyms defined as:

yellow ochre and yellow ocher: pigment consisting of a limonite mixed with clay and silica

yellow ochre (noun)	yellow ocher (noun)
pigment consisting of a limonite mixed with clay and silica	pigment consisting of a limonite mixed with clay and silica