Webster has missed the interesting note that 'puddle' is the diminutive form of the Old English word pudd, meaning 'ditch' or 'furrow'.
While historically puddle has been used to refer to small pools and ponds as well as the smaller rain puddles, today we tend to use it mostly for quite small poolings of water, and specifically for those that we expect to drain away of evaporate in a matter of hours or days.
Iron Noder