Bernoulli's theorem

1 [after Jacques Bernoulli] :  a basic principle of statistics: as the number of independent trials of an event of theoretical probability p is indefinitely increased, the observed ratio of actual occurrences of the event to total trials approaches p as a limit —called also law of averages

2 [after Daniel Bernoulli] :  a law of hydrodynamics: in a stream of liquid the sum of the elevation head, the pressure head, and the velocity head remains constant along any line of flow provided no work is done by or upon the liquid in the course of its flow and decreases in proportion to the energy lost in viscous flow — see head 14b