noun
folding umbrella; collapsible umbrella
A compact umbrella that folds down to a smaller size. Often synonymous with 折りたたみ傘, though 折り傘 may emphasize the folding mechanism.
See also: 折りたたみ傘
急な雨に備えて、折り傘をカバンに入れておく。
I keep a folding umbrella in my bag in case of sudden rain.
More explicitly describes the folding action; often interchangeable, but 折りたたみ傘 can feel slightly more descriptive.
Compound of 折り (ori, 'folding', from verb 折る) and 傘 (kasa, 'umbrella').