Wiktionary
field house
n. 1 (lb en rare) A tent. 2 (context North America English) A large building for indoor sports, particularly at colleges. 3 (context North America English) A building for equipment storage and changing rooms (locker rooms) by an outdoor sports field.
WordNet
field house
n. a building for indoor sports [syn: sports arena]
an athletic facility where athletes prepare for sport
Wikipedia
Field house
Field house or fieldhouse is a common name for indoor sports arenas and stadiums, mostly used for college basketball, volleyball, or ice hockey. Additionally it is known to serve as a support building for various adjacent sports fields, i.e. locker room, team room, coaches offices, etc.
This American English term dates from the 1890s.