Sidewalk: a paved walk at the side of a road or street.
My dictionary doesn’t mention level or smooth. It also does not expand the definition to fit the common usage of walkways not beside roads or streets – such as between buildings in an apartment complex, or connecting points of interest on a college campus.
In a perfect world a sidwalk would be smooth. Small children with bare feet would not stub their toes. Wheels attached to roller skates, skateboards, and luggage would roll smoth and steady. Distracted strollers could contemplate the weather or abstract concepts as they walked.
But reality intrudes. Accommodations are required. Choices need to be made.
This is a path best taken awake and aware.