Double acrostic is a type of puzzle that involves two sets of words or phrases that are revealed by their first and last letters. Some synonyms for double acrostic are "dual acrostic," "twin acrostic," "paired acrostic," or "double edged acrostic." These terms all refer to the same type of puzzle that requires the solver to find two sets of words or phrases that are related in some way. Double acrostic puzzles can be challenging but rewarding to solve, as they often require an extensive vocabulary and a keen eye for detail. With practice, anyone can learn to solve these intriguing puzzles.