The story
The h stands for “highly cited” and Hirsch, since the metric was suggested in 2005 by physicist Jorge E. Hirsch.
Etymology from Wiktionary, CC BY-SA 4.0.
h-index
Today it means: An author-level metric that attempts to measure both the productivity and the citation impact of the publications of a scientist or scholar, based on a set of most cited papers and the number of citations in other publications. Full definition →