Wife or Widow or a Chief, Chieftain or Laird
Wife of a Chief, Chieftain or Laird
Some wives of chiefs or chieftains use the designation of 'Mrs', others have adopted the Irish style of 'Madam', eg Madam Chisholm, which has met with the Lord Lyon's approval. To be sure of the designation preferred, you must check with an individual family.
Widow of a Chief, Chieftain or Laird
The style of the Dowager Mrs (or Madam) [Maclean of Ardgour] is now seldom used, but when the widow of a deceased Chief, etc, is living under the same roof as the wife of the current Chief, this identification is useful.