What is (a) The upright piece of a step, from tread to tread. Hence: (b) Any small upright face, as of a seat, platform, veranda, or the like called?

riser — (Arch.) (a) The upright piece of a step, from tread to tread. Hence: (b) Any small upright face, as of a seat, platform, veranda, or the like. (Webster's 1913.)

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