. General: Allowable departure from a specification or standard, considered non-harmful to the functioning of a part, process, or product over its life cycle.
2. Engineering: Ability of an item or system to withstand high levels of stress or overloading without suffering irreparable harm. See also safety factor.
3. Environmental: Permissible residue level for a pesticide in raw agricultural produce and processed food. All registered pesticides for use on a feed or food crop have their tolerance levels established by a regulatory agency such as the EPA.