(noun)
the capacity to allow (tolerate) the existence of behavior and/or opinions that differ from one's own, especially when one disagrees with or dislikes them;
e.g. He preaches a manner of tolerance and suggests that we allow people to follow their own customs and traditions.
(noun)
the ability to endure constant hardship, subjugation, or pain;
e.g. She has a high pain tolerance, and she can hold very hot things without dropping them.
(noun)
in medical usage, broadly, the capacity of an organism to withstand and thrive in some unfavorable condition, such as the capacity to become less responsive to some drug due to repeated exposure;
e.g. The doctor doesn't want him to gain tolerance for the medicine, so she is controlling his dosage.
(noun)
the variation or deviation from some standard that is allowable, especially the range within which variations are allowed when setting the dimensions of a piece/component of a machine;
e.g. The tolerance for this pulley is just about one millimeter.