Late Latin Dominicus, "of the Lord" (Latin dominus, of a lord) -- having to do with Jesus as the Lord; having to do with the Lord's Day (Sunday). Dominical letter is any of the first seven letters in the alphabet as used in church calendars to indicate Sundays -- the letters are assigned to the first seven days of January, and the letter falling to Sunday is the arbitrary symbol for Sunday the rest of the year.
Dominical is a beach-front town in the province of Puntarenas in Costa Rica approximately 45 km south of Quepos. It's famous for large, year-round waves and is well-known by most surfers in Costa Rica. The town began as a small fishing village but has since grown into a tourist destination most notably for surfers.