Origin: Germanic Old English suffix
Capaciousness has 3 different meanings across 1 category:
intellectual breadth
"the very capaciousness of the idea meant that agreement on fundamentals was unnecessary"
"his unselfishness gave him great intellectual roominess"
spatial largeness and extensiveness (especially inside a building)
"the capaciousness of Santa's bag astounded the child"
"roominess in this size car is always a compromise"
"his new office lacked the spaciousness that he had become accustomed to"
The quality of being capacious.