What does "step-through" mean?

An open space in an otherwise solid object through which a person can step or walk.

Step-through

noun

noun ·Rare ·Advanced level

Noun

1
An open space in an otherwise solid object through which a person can step or walk. attributive
"A motor-scooter has a step-through frame, also known as an "open frame"."

"A motor-scooter has a step-through frame, also known as an "open frame"."