cocoa are the substances used to make chocolate . cocoa solids refer to that they are not natural , they are solids just like cocoa

If your talking about cocoa solids, then white chocolate is the lowest percent chocolate made as it has none. It is made with the cocoa butter but not the solids.

White chocolate: is a confection of sugar, cocoa butter, and milk solids. Unlike chocolate, white chocolate contains neither chocolate liquor nor cocoa solids. Because white chocolate contains neither cocoa solids nor chocolate liquor (cocoa mass), it does not meet the standard to be marketed as chocolate in many countries.

Cacoa beans, also called cocoa beans, are the dried and fermented fatty beans from which cocoa solids and cocoa butter are extracted.

Finely ground cocoa beans (nibs). It contains both cocoa solids and cocoa butter (it hasn't been separated yet). Also known as "cocoa mass" and more commonly, "chocolate liquor".