fundraising activities; fund-raising campaign
Refers to organized efforts to collect donations, often for charity or disaster relief.
We carried out fundraising activities for the earthquake-affected areas.
I saw people doing a street fundraising campaign.
募金 is the act of collecting donations or the collected money itself, while 募金活動 specifically refers to the organized activities or campaign.
寄付 means donation or contribution, focusing on the act of giving, whereas 募金活動 is about the organized effort to gather such donations.
Compound of 募金 (ぼきん, 'fundraising') and 活動 (かつどう, 'activity').