Zonal and meridional
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The terms zonal and meridional are used to describe directions on a globe. Zonal means "along a latitude circle" or "in the east-west direction"; while meridional means "along a meridian" or "in the north-south direction".
These terms are often used in the atmospheric and earth sciences to describe global phenomena, such as "meridional wind flow", or "zonal temperature". For vector fields (such as wind speed), the zonal component (or x-coordinate) is denoted as u, while the meridional component (or y-coordinate) is denoted as v.