Futon and Mattress

Futon noun - Mattress consisting of a pad of cotton batting that is used for sleeping on the floor or on a raised frame.

Mattress and futon are semantically related In some cases you can use "Mattress" instead a noun "Futon".

Mattress noun - A large thick pad filled with resilient material and often incorporating coiled springs, used as a bed or part of a bed.

Futon and mattress are semantically related in bedding topic. You can use "Futon" instead a noun "Mattress".