indeterminacy

When the colored thing is something whose color appearance changes as the quality of the daylight changes, e.g. the sea, there may be no simple answer to questions which seek to pinpoint the real color. Is the sea really green or grey or blue? Or greenish-blue or bluish-grey or grayish-bluish-green? Again we should not be too perturbed by indeterminacy.

-- Mark Johnston "How to Speak of the Colors" Readings on Color ed. Alex Byrne and David R. Hilbert