"Puddle weld. A nonstandard term for an arc spot weld or plug weld."- from "Standard Welding Terms and Definitions".
"Plug or slot weld" symbol is a rectangle on the weld arrow.
"Spot or projection" is a circle, either tangent to the weld arrow or centered on the weld arrow when there is no "side" significance.
From "Standard Symbols for Welding, Brazing and Nondestructive Examination".