The term 'START OF A GUINNESS RECORD' can be summarized as the word 'MOST', which is a four-letter word. The Guinness World Records is an annual publication that contains a collection of world records, both human achievements and the extremes of the natural world. It is widely recognized as the authoritative source for world records, and has been published since 1955. The records in the book are based on the highest or lowest achievement, and the term 'START OF A GUINNESS RECORD' refers to the beginning of a record-breaking attempt.