filled with vascular sinuses and capable of becoming distended and rigid as the result of being filled with blood; "erectile tissue"; "the penis is an erectile organ"
being or suggesting a cavern; "vast cavernous chambers hollowed out of limestone"
A cavernous room or building is very large inside, and so it reminds you of a cave. The work space is a bare and cavernous warehouse. a cavernous room, space, or hole is very large and deep