What's the H-index?

Devised by Jorge Hirsch, the H-index is the highest number of papers an author has that have each received at least that number of citations. This may be fairer than counting total papers or just high-ranked articles, and can't be self-inflated. Someone with an h-index of 10 has written 10 papers that each had at least 10 citations. 

H-index (Publish or Perish)