idea; plan; proposal; suggestion; (legislative) bill — an idea or plan presented for consideration. Also used as a suffix (e.g., ～案 for bills/proposals).
新しい販売促進の案を上司に提出した。
I submitted a new sales promotion plan to my boss.
いい案が思い浮かばないときは、みんなでブレインストーミングをする。
When no good ideas come to mind, everyone does brainstorming together.
その法案は国会で審議中の案だ。
That bill is a proposal currently under deliberation in the Diet.
draft; rough copy — a preliminary version of a document, plan, or proposal not yet finalized.
企画案の第一案をメールで共有した。
I shared the first draft of the project proposal by email.
設計の原案を見直して、修正点をまとめた。
I reviewed the initial design draft and summarized the points to be revised.
expectation — used in words/phrases expressing expectation or supposition (e.g., in the phrase 案の定 meaning 'as expected').
案の定、約束の時間に彼は来なかった。
As expected, he didn't come at the appointed time.
案に基づいて対応を検討する必要がある。
We need to consider measures based on the proposal/plan.
desk; stand — archaic meaning (rarely used in modern Japanese).
古い文献では、『案』が机の意味で用いられている箇所がある。
In old documents, there are passages where '案' is used to mean a desk.