When I look at the current Twitter trends for the United States, I find tags like:
#SEAvsMIN#SundayFunday#IShouldNotBeAllowed#MakeAShowChildishWhen investigating further, one can find out, that by #SEAvsMIN the NFC match between Seattle Seahawks Minnesota Vikings is meant.
But what about the other, less meaningful hashtags?
Is there any way to get definitions of them programmatically?
Is there a resource (maybe an API) which can provide information about such hashtags?
No, there isn't. There is no central repository of hashtags, much less their definitions. The definition is whatever the majority of people who use it say it is. Anyone can make up a hashtag; it only becomes useful if other people decide to use it.
Some entities try to promote some organization. The NFL, as you've seen, promotes hashtags of the form {abbreviation of visiting team}vs{abbreviation of home team}. But, as I said, anyone can create a hashtag just by using it.
See also: https://en.wikipedia.org/wiki/Hashtag
There is no way of getting a definition of all possible hashtags ever made. Hashtags are a community-created way of organising information on Twitter. And because of their grassroots origin, they are still a very open, egalitarian tool: anyone can create (randomly make up with no real rules) and use any hashtag. There are new hashtags created all the time, therefore no such list can exists to define what each means.
