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[for a liquid] to fill up and spill over. The laundry tub finally welled over as it became too full. The milk glass began to well over, and Timmy began to cry.
1. To build up and overflow the boundaries of a container: I left the tap on, and the water in the bathtub welled over and spilled onto the floor. Tears welled over and ran down my cheeks. My anger welled over, and I yelled out.
2. To become filled and overflow: My eyes welled over with tears. My heart welled over with joy.