共催(きょうさい)

共催(きょうさい) means co-hosting or joint sponsorship — when two or more organizations share responsibility for organizing an event.

Usage

• Functions as a する verb and as a noun.
• Constantly appears on event flyers, programs, and official announcements alongside related sponsorship roles.
• The prefix 共(きょう)～ means 'together, joint': 共同(きょうどう) (joint, cooperative), 共有(きょうゆう) (sharing).

Common patterns

• A社(しゃ)とB社(しゃ)が共催(きょうさい)する (companies A and B co-host)
• 共催(きょうさい)イベント: a co-hosted event
• 主催(しゅさい)：A、共催(きょうさい)：B、後援(こうえん)：C: 'Organized by A, co-hosted by B, supported by C' (typical event-flyer credit line)
• 国際(こくさい)会議(かいぎ)を共催(きょうさい)する (to co-host an international conference)

Similar words

• 主催(しゅさい): hosting/organizing (by a single primary organizer).
• 後援(こうえん): support/patronage (a less active backing role, often by a public agency).
• 協賛(きょうさん): sponsorship (typically financial support from a company).
• 協力(きょうりょく): cooperation (the broadest, vaguest support credit).