definite plan; finalized proposal
Refers to a plan or proposal that has been formally decided or finalized, often in business, policy, or legal contexts.
来年度の予算案はまだ成案に至っていない。
The budget proposal for next fiscal year has not yet been finalized.
After many meetings, we finally arrived at a finalized plan.
It took time to reach a definite plan in the committee.
The committee plans to put together a finalized proposal by next month.
After a long discussion, we finally reached a finalized plan.
草案 is a rough, unfinished draft, whereas 成案 is the completed, approved plan that results from it.
原案 is the original proposal before revision, while 成案 is the version finally settled on after deliberation, so learners often mix up which stage each word marks.
Compound of 成 (sei, 'become, complete') and 案 (an, 'plan, proposal'). The exact historical derivation is uncertain, but the word has been used in formal Japanese to mean a finalized plan.