What is the term for the boundary between two different air masses that results in little vertical motion and often results in cloudy conditions?

<p style=";text-align:left;direction:ltr">Arab Weather - The term used to describe the boundary between two different air masses, which results in little vertical movement and cloudy conditions, is a stationary front. In this case, the two air masses are unable to move significantly, which leads to stable weather and cloud accumulation, often associated with light or continuous rain.</p>