Definition of momentaneity in English:

momentaneity

Pronunciation /ˌməʊm(ə)ntəˈneɪɪti/ /ˌməʊm(ə)ntəˈniːɪti/

noun

rare
  • Transitory character; momentariness.

Origin

1920s; earliest use found in D. H. Lawrence (1885–1930), writer. From momentaneous + -ity; compare -eity.