The term CSA Monogram is a reference to the Confederate States of America, which was a government formed by 11 southern states during the American Civil War. The three crossword solutions REL (3 letters), RELEE (5 letters) and REB (3 letters) are all abbreviations for roles within the CSA. REL stands for 'Regiment of Light Infantry', RELEE stands for 'Regiment of Light Artillery' and REB stands for 'Regiment of Cavalry'.