The term 'season starter' can be broken down into three crossword solutions: OPENER (6 letters), OPEN (4 letters), and pre (3 letters). An OPENER is something that begins or starts something, such as a show or event. OPEN is an adjective meaning not closed or blocked off. Pre is a prefix meaning before or in front of. Together, these words can be used to describe the beginning of a season, such as the start of summer or winter.