From Longman Dictionary of Contemporary Englishriserris‧er /ˈraɪzə $ -ər/ noun [countable] 1 → early/late riser2 technicalTB the upright part of a step on a set of stairs3 → risers
Examples from the Corpus
riser• A much larger crowd of cameras and reporters stood on a riser in the back.• A red squirrel was another early riser.• There was the possibility of kingfisher and water rail for early risers on the morrow.• By the evening they are still full of energy when the early risers wilt.• We were early risers on the first morning.• Graduate students in most institutions are notoriously late risers, who work way past conventional bedtime.• These risers can be square, oblong or round, hollow or solid. 