Translation guide
The English adverb 'jointly' means doing something together with others, sharing responsibility or effort. In Japanese, this concept is expressed through adverbs, compound verbs, or phrases that emphasize collaboration, shared action, or co-ownership.
Expressing that an action is done by two or more people or parties together, sharing the effort.
The most common and neutral way to say 'jointly'. Used for collaborative projects, research, ownership, etc.
このプロジェクトは二つの会社が共同で行っています。
This project is being carried out jointly by two companies.
彼らは共同で新しい製品を開発した。
They jointly developed a new product.
Emphasizes cooperation and working together. Slightly more about the act of cooperating than just sharing ownership.
地域の人々が協力して祭りを準備した。
The local people jointly prepared the festival (by cooperating).
Specifically for signing or issuing something jointly, like a letter or statement.
両社の社長が連名で声明を発表した。
The presidents of both companies issued a statement jointly.
Indicating that something is owned, managed, or held by two or more parties together.
Used for jointly owned property, accounts, or responsibilities. Often followed by a noun.
私たちは共有の口座を持っています。
We have a joint account.
この土地は兄弟で共有している。
This land is jointly owned by the brothers.
A more explicit phrase meaning 'to own jointly'. Useful when you need a verb phrase.
彼らはその特許を共同で所有している。
They jointly own the patent.
A specific legal phrase meaning each party is liable both together and individually.
Used in legal contexts for 'jointly and severally'. Often paired with '責任を負う' (bear responsibility).
彼らはその負債について連帯して責任を負う。
They are jointly and severally liable for the debt.
While 一緒に (いっしょに) means 'together' in a general sense, 共同で implies a more formal or organized collaboration, often for a specific purpose or project. Use 一緒に for casual activities like eating or going somewhere.
一緒に映画を見に行かない？
Want to go see a movie together?
共同で研究を行う
conduct research jointly