While throwing stones in water, we will see lots of small rings formed. Can anyone say single word for the rings formation?.
Ripples is the word that describes this phenomenon.
OALD: a small wave on the surface of a liquid, especially water in a lake, etc The air was so still that there was hardly a ripple on the pond's surface.
Ripples on a lake
A capillary wave is a wave traveling along the phase boundary of a fluid, whose dynamics are dominated by the effects of surface tension.
While throwing stones... single word for the rings formation?
How about waves ?
"Surface waves in water" http://en.wikipedia.org/wiki/Wave
For a difference with ripples and swell, cfr: http://www.naturalnavigator.com/the-library/ripples-waves-and-swell
"Ripples are the instant effect of wind on water and they die down as quickly as they form, as the surface tension of the water dampens their efforts"
There could be multiple correct answers to the question, depending on the perspective or specific context from which it's asked.
The adjective concentric can be applied to rings or circles to characterize a set of them that have a common center.