IPA: /ˈlɔːŋnəs/
KK: /lɔŋnəs/
The quality or state of being long; the measurement of something from one end to the other.
The longness of the river surprised the hikers as they followed its winding path.
Longness → It is formed from "long" (from Old English "lang", meaning having a great distance or duration) and "-ness" (a suffix used to form nouns indicating a state or quality). The word "longness" refers to the state or quality of being long.
Think of the word 'long' which describes something that has a great distance or duration, and remember that 'longness' means the quality of being long.