0 ruling at the present time or at a particular time, or relating to the period when a king, queen, etc. is ruling :
Mary, Queen of Scots was Scottish queen regnant from 14 December 1542 to 24 July 1567.
I did hear once that Prince Charles is considering taking as his regnant name as King George VII.
That is the ideology that is regnant in France.
Failure to meet the psychological needs of the developing child can be a regnant cause of personality disorders.
Isabella was Queen regnant of Castile and Leon.
King Edward I of England executed David, the last prince regnant of Wales, in this fashion.
As an art critic, I was constantly adjusting to yet resisting this regnant, aloof individualism.
A couple of months ago, it may have been possible to believe that such an ideology was regnant.
