Banister and Grab bar

Banister noun - A protective barrier consisting of a horizontal bar and its supports.

Grab bar and banister are semantically related in rail topic. In some cases you can use "Grab bar" instead a noun "Banister", when it comes to topics like balustrade, handrail.

Grab bar noun - A bar attached parallel to a wall to provide a handgrip for steadying yourself.

Banister and grab bar are semantically related in rail topic. You can use "Banister" instead a noun phrase "Grab bar", if it concerns topics such as balustrade, handrail.