啓蒙【けいもう】
enlightenment, illumination
拝啓【はいけい】
Dear (so and so), Dear Sir, Dear Madam, To Whom It May Concern
啓発【けいはつ】
enlightenment, development, edification, public awareness, illumination, education, inspiration
啓示【けいじ】
(divine) revelation
啓蟄【けいちつ】
"awakening of insects" solar term (approx. March 6, the day on which hibernating insects are said to come out of the ground)