, a stochastic process
is said to be ergodic if its statistical properties (such as its mean and variance) can be deduced from a single, sufficiently long sample (realization) of the process.
One can discuss the ergodicity of various properties of a stochastic process. For example, a wide-sense stationary process
has mean 
and autocovariance
which do not change with time.
This house is so full of people, it makes me sick! When I grow up and get married, I'm living alone!
[in his mind] I wish they would all just disappear.
I took a shower, washing every body part with actual soap, including all my major crevices, including in between my toes and in my belly button, which I never did before but sort of enjoyed. I washed my hair with adult-formula shampoo and used cream rinse for that just-washed shine. I can't seem to find my toothbrush, so I'll pick one up when I go out today. Other than that, I'm in good shape. [applies aftershave] AAAAAAAAAAAAAAAAAGHHHHHHHHHHHH!
A Family Comedy Without The Family.
When Kevin's Family Left For Vacation, They Forgot One Minor Detail: Kevin. But Don't Worry... He Cooks. He Cleans. He Kicks Some Butt.
This Non-Family Comedy is a Real Scream.