In typical normal human speak, a gift and donation are effectively equivalent, but differ by the recipient. A donation is given to an organization, a gift is given to an individual.
If you give to a single individual on the street, it would typically be considered a gift. If you gave to a collective on the street, then it would typical be considered a donation.
Of course, humans are at their best when not normal. If you want to call giving to an individual a donation, go nuts. Hell, if you want to call it the moon, even better.
Sampling 5 online dictionaries I am not seeing this nuance. Although sure, we can agree that a donation is a gift. In my opinion the actual nuance is that a donation is a gift driven by charitable intentions. A gift has broader connotations, like romance or celebration. A donation probably implies the gift is not driven by a personal connection to the receiver.
If you give to a single individual on the street, it would typically be considered a gift. If you gave to a collective on the street, then it would typical be considered a donation.
Of course, humans are at their best when not normal. If you want to call giving to an individual a donation, go nuts. Hell, if you want to call it the moon, even better.