The term 'OPENING WORD' can be represented by five different words, each with a different number of letters. The first word is 'HELLO' which has five letters and is a common greeting used to start a conversation. The second word is 'DADA' which has four letters and is a term used to refer to a father. The third word is 'SESAME' which has six letters and is the title of a popular children's show. The fourth word is 'MAMA' which has four letters and is a term used to refer to a mother. The fifth word is 'ONE' which has three letters and is a number that is often used to signify the beginning of something.