I've yet to find a satisfying definition for a 'person of color.' Its meaning may be clear in some contexts, but I don't think general conversations and open social commentaries are among those settings. The meanings I hear most commonly- 1) people without the physical characteristics which first appeared in western Europe, and 2) people who do (or would) experience racism under western white supremacy. (perhaps equivalent to #1) I realize critiquing these at this point risks a straw-man argument, but it seems both allow someone to very easily transition, with sufficient body modification, into being 'of color.' (The earlier response, regarding Caucasian lineage, led to an unpleasingly simple conclusion.) It is hard to define the concepts we use to understand reality. Searching for and discovering their illogical implications is important if we wish to understand the errors in our perspective. If my looking for inconsistencies and contradictions is a "gotcha" move, it is only because we need to be gotten. Generalization and ambiguity are not without value, but in such an important subject I think clarity and precision should be required.