first half of a Diet session; Diet session up to the budget creation
Refers to the period of a regular Diet session before the budget is passed, typically from January to around March. Used in Japanese political contexts.
During the first half of the Diet session, the budget bill is deliberated.
Refers to the latter half of a Diet session, after the budget is passed. 前半国会 is the earlier part focused on budget creation.
Compound of 前半 (first half) and 国会 (Diet, parliament). A straightforward modern political term.