noun
completion ceremony
A formal ceremony held to mark the completion of a construction project, such as a building, bridge, or other structure.
新しい橋の竣工式が来週行われます。
The completion ceremony for the new bridge will be held next week.
Variant spelling using 功 (achievement) instead of 工 (construction). Less common but still used.
落成式 also means a completion ceremony, but is more commonly used for buildings. 竣工式 is broader and can be used for various construction projects.
竣工 (しゅんこう) means 'completion of construction', from 竣 (finish) and 工 (construction). 式 (しき) means 'ceremony'. The variant 竣功式 uses 功 (achievement) instead of 工.