Definition from Wiktionary, the free dictionary
- (aviation) Acronym of Ceiling and visibility [are] OK., sometimes alternatively interpeted as "Clouds and...", a weather status report for pilots when visibility is at least 10 kilometres, there are no clouds below 5000 feet or minimum sector altitude (whichever is higher), and there is no current or forecast significant weather such as precipitation.
- When appropriate, this term can be used in ATIS broadcasts in lieu of detailed weather information.
- "CAVOK" may appear within METAR format weather report strings in place of the standard "Visibility Group (VVVVVSM)" as defined in Section 12.6.6 of the US "Federal Meteorological Handbook No. 1" (September 2005).