equanimity – calmness especially in a difficult situation
(Pronounced eh-kwuh-nim-uh-tee)
To remember the definition of the word equanimity, use the following mnemonic:
Equality for all the animals in this city (equanimity) was suggested to all the animals as they sat calmly in a circle.

Examples of equanimity in a sentence
She maintained her equanimity during the argument.
Their manager wasn't known for his equanimity.
He found meditation helped maintain his equanimity.