Holly and holiday are Christmas words. Hark The Herald Angels Sing is a Christmas carol.
hope
Hubble telescope is a space word. It begins with the letter h.
harvest
honesty is a seven letter word that begins with h
happen
Half
Hubble telescope is an outer space word. It begins with the letter h.
hydrogen
hypoxia
holy
horrifyin
habanero
Haughty is another word for arrogant that begins with the letter H.