noun
joint signatures; co-signing
Refers to the act of multiple people signing a document together, or the signatures themselves. Often used in legal, business, or formal petition contexts.
請願書には多くの市民の共同署名が集まった。
The petition gathered many joint signatures from citizens.
契約書に共同署名をする前に内容をよく確認してください。
Please check the contents carefully before co-signing the contract.
Compound of 共同 (joint, cooperative) and 署名 (signature). The exact historical derivation is uncertain, but the word follows standard Sino-Japanese compounding patterns.