Technically, whether you use a/an before a word beginning with an H should be determined by the letter after the H. Thus, "an hand" is technically correct. Only if the h is silent, if I'm not mistaken. It would not be correct to say "I want an hamburger." Nor "have an happy holiday." I believe you're right (such as an historic moment; the word is pronounced "istoric" with the "h" silent). Yes, historic and honor were the words that immediately came to mind. There are a number of formal "correct" English pronunciations which drop the h altogether when deciding between a or an. Link. Back in undergrad, one of my friends was a linguistics major who did a lot of work on this kind of stuff. There was an English grammar book he showed me which stated that you should always drop the h when determining whether to use a or an. It's a dialectical thing (as seen with some people pronouncing the "h" in history), but technically speaking, it is acceptable to say "an hand" or "an happy holiday."