IPA: /ˈraɪzər/
KK: /ˈraɪzər/
A person who gets up early or a platform that raises something to a higher level, like a stair step or a stage.
The riser allowed the audience to see the performance better from the back of the room.
Riser → The word is formed from "rise" (from Old English "rīsan", meaning to get up or ascend) and the suffix "-er" (meaning a person who). A riser is a person or thing that rises or ascends.
Think of someone who is 'getting up' ('rise') — the '-er' indicates that this person is doing the action of rising.