/i lawng gay"sheuhn, i long-, ee'lawng-, ee'long-/ , n.
1. the act of elongating or the state of being elongated.
2. something that is elongated.
3. Astron. the angular distance, measured from the earth, between a planet or the moon and the sun or between a satellite and the planet about which it revolves.
[ 1350-1400; ME elongation- (s. of elongatio ), equiv. to elongat ( us ) (see ELONGATE) + -ion- -ION ]