The most widely used is hon-do, which can be translated indeed as "main hall", but this name appeared only during the Heian Period. Older temples, like the Shitennoji from Osaka (which was established in 593 during the Asuka Period), are designating their main building as kon-do 「金堂」, "golden hall". Here is the Shitennoji kon-do, a true jewel of Buddhist architecture...
EXIF info:
Nikon D300
Lens: 8-16mm F/4.5-5.6G
Focal Length: 9mm
Aperture: F/7.1
Shutter Speed: 1/1250s
ISO Sensitivity: ISO 200