The Vietnamese word "nệm" is a noun that primarily means "mattress" or "bed." It refers to the soft material that you lay on when sleeping, usually placed on top of a bed frame.
While "nệm" mostly refers to a mattress, it can sometimes be used in a broader sense to refer to any soft surface you might lie on, such as cushions or bedding in general.
In summary, "nệm" is an essential word for talking about sleep and comfort in Vietnamese.