UN: the Universal Declaration of Human Rights (1948) mentions the word tolerance once, without defining it, in the paragraph on the right to education:
Article 26, point 2:
Education shall be directed to the full development of the human personality and to the strengthening of respect for human rights and fundamental freedoms. It shall promote understanding, tolerance and friendship among all nations, racial or religious groups, and shall further the activities of the United Nations for the maintenance of peace.
The UNESCO Declaration on Tolerance adds the following elements of definition:
- Tolerance is harmony in difference. It is not only an ethical obligation; it is also a political and legal necessity.
- Tolerance is a virtue that makes peace possible and helps to replace the culture of war with a culture of peace.
See the usual definitions of the word tolerance in this dictionary, which highlight the rather negative connotations of the noun tolerance and the verb tolerate.