streamer
noun [ C ] uk/ˈstriː.mər/ us/ˈstriː.mɚ/
(DECORATION)
装饰彩纸条，饰带
a long, narrow strip of brightly coloured paper that is used as a decoration for special occasions such as parties
We decorated the office with streamers for Paul's leaving party. 为了给保罗办个告别会，我们用彩带装饰了一下办公室。