Science / Weather / Obscuration: Any phenomena in the atmosphere, excluding precipitation, that reduces horizontal visibility. According to the National Weather Service, some of the obstructions to visibility include blowing and widespread dust, fog (including freezing fog and patchy fog), haze, mist, sand and blowing sand, smoke, blowing spray, and volcanic ash. It is reported as 'X' in an observation and on the METAR.
Science / Weather / Partial Obscuration: Denotes that 1/8th or more of the sky, but not all of the sky, is hidden by any surface-based phenomena in the atmosphere, excluding precipitation. It often reduces horizontal visibility but not the v MORE
Business / Finance / Clear: In the context of general equities, 'make all your obligated calls'; check with all prior obligations in a security. Often preceded by 'subject to.' MORE