Definition from Wiktionary, the free dictionary
momentaneous (not comparable)
- (grammar) Of or relating to a grammatical aspect relating to an action that takes place at a specific point in time.
- (archaic) momentary
1827, John Claridge, The Shepherd of Banbury's Rules to Judge of the Changes of the Weather, Grounded on Forty Years' Experience:
- Lightning is a great flame, very bright, extending every way to a great distance, suddenly darting upwards, there ending, so that it is only momentaneous.