Mattress
Nancy Randolph lying on a mattress
A mattress was a large, flat object used for sleeping. In some situations, it might be placed on top of a bed.
When the crew of Enterprise NX-01 was forced to hide in the catwalk in 2152, they brought sleeping mats and mattresses with them. (ENT: "The Catwalk")
In 2266, Harcourt Mudd located the missing Venus drug pills in his mattress. (TOS: "Mudd's Women")
Navigator Nancy Randolph lay on a mattress while ill at the Lactra VII zoo in 2269. (TAS: "The Eye of the Beholder")
According to Miles O'Brien, Cardassian mattresses were uncomfortable. (DS9: "Q-Less")
In 2370, while undergoing treatments to adjust to Deep Space 9's gravity, Melora Pazlar complained to Doctor Julian Bashir that her mattress felt like rocks. (DS9: "Melora")
Prior to revealing her true gender that year, Pel told Quark she couldn't sleep on a lumpy mattress. (DS9: "Rules of Acquisition")