Oh, we thought you said sinner and were preparing a very long answer! To simmer, though, is nearly the same thing – to get into very hot water, but mercifully stopping just before you cross the line to boiling.

Simmering water is water just below the boiling point, say, between 200°F and 211°F (93°C and 99°C) at sea level, generally characterized by very small bubbles that rise to the surface. To simmer is to cook food in any simmering liquid, including water, wine, fruit juice, stock, beer, milk, cream, yogurt, etc.