Where the sidewalk ends

CURB

The concrete edge that separates pedestrians from the street often has a slight drop-off.

The phrase "Where the sidewalk ends" is a playful nod to Shel Silverstein’s famous children’s poetry book, but in this crossword, it’s taken literally. The "end" of a sidewalk is the raised edge that separates it from the street—commonly called the "curb." The clue relies on interpreting the phrase in a concrete, physical sense rather than its poetic meaning. It’s a straightforward definition once you think about the real-world location.