The vertical movement of heat and moisture, especially by updrafts and downdrafts in an unstable air mass. The terms convection and thunderstorm are often used interchangeably, although thunderstorms are only one form of convection. Towering cumulus clouds are visible forms of convection.
The transmission of heat in a fluid by the circulation of currents.
Deviation from the mean orbit of a heavenly body.
The act of varying; a partial change in the form, position, state, or qualities of a thing.
The angular difference at the vessel between the direction of true north and magnetic north.
A related but distinct thing.
A line of play that differs from the original.
The modification of a hereditary trait.
A technique where material is repeated with alterations to the melody, harmony, rhythm, timbre, texture, counterpoint or orchestration; but with some invariant characteristic, e.g. a ground bass.