A moment is a medieval unit of time equal to 1.5 minutes or
1/40 of an hour. In modern English it usually refers to "a very brief period of time", the exact length remaining ambiguous. The reference is from
John of Trevisa, writing in 1398 that there are 40 moments in an hour (thus the
90 seconds). However, this definition is from an archaic version of the Oxford
English Dictionary and is not in current usage today. So it would be more
accurate to say that while a medieval moment was ninety seconds, modern moments
are much shorter.
