The term 'FIRST SIDE TO VOTE' can be solved by the crossword solutions YEAS and AYES, both of which are four letters long. YEAS is an archaic spelling of the word 'yeas, ' which is used to indicate a vote in favor of something. AYES is another archaic spelling of the same word, and is also used to indicate a vote in favor of something. Together, these two words refer to the first side to vote in a given situation.