Once upon a time, in the days of yore in the Land of Grammar, people used to say things such as:
As far as county towns go, Hertford’s nice but a bit quiet.
As far as small pets go, guinea pigs are pretty good.
As far as laws go, it’s rather old-fashioned.
‘As far as X goes’ means: ‘To the degree that X is considered or exists’. As far as definitions go, that’s the best I can manage.
The problem is … people have wilfully started dropping the ‘go’ and the ‘goes’, like schoolkids dropping chocolate wrappers. I have no idea why, but it makes me apoplectic with rage. Yes, as far as grammar, I’m pedantic.