A normal tent used for camping with the bottom cut out fitted around a mattress. Not to be confused with a normal bed tent, which will usually not be completely enclosed
"Yo, check out this bed tent I got to feel cozy"
"That's not a bed tent, that's a Fortress Bed Tent"
An erection in the morning that makes your covers look like a tent
"Yeah I slept really well last night, woke up with a bed tent"