general framework; outline; broad outline
Refers to the overall structure, rough plan, or big picture of something, without going into details.
Let's decide on the general framework first, and then work out the details.
His explanation is correct in broad outline, but there are errors in the details.
Compound of 大 (おお, 'big') and 枠 (わく, 'frame'). The literal meaning is 'big frame', which extended to 'general framework' or 'outline'.