The term 'At FIRST' can be expressed in a variety of ways, such as 'INITIALLY' (9 letters), 'ORIGINALLY' (10 letters), 'Erst' (4 letters), and 'Onbase' (6 letters). INITIALLY is defined as 'at the beginning, ' while ORIGINALLY means 'in the beginning.' Erst is an archaic word meaning 'FIRST' or 'at FIRST, ' and Onbase is a term used to describe a situation in which someone is in a position of advantage. All of these words refer to the same concept of something happening at the start or in the beginning.