Learner's definition of TALL
1 : greater in height than the average person, building, etc.
All the children in my family grew up to be very tall.
My mother is short but my father is fairly tall.
The giraffe is the tallest animal.
the tallest [=highest] mountain
the world's tallest building
The drinks were served in tall glasses.
2 always used after a noun : having a specified height