longest
adjectiveUK /ˈlɒŋ.ɡɪst/
US /ˈlɔːŋ.ɡɪst/
The longest thing is the one that is the most long of all.
The blue whale is the longest animal in the sea.
OTHER MEANINGS
2. Taking the most time of all.
That was the longest movie I have ever watched.
3. Being the tallest or most extended in size.
She has the longest hair in her class.
4. Continuing for the greatest distance.
This is the longest road in the whole town.