The term 'ACROSS PREFIX' refers to three prefixes that are commonly used in words related to transportation. The prefix 'TRANS' is five letters long and means 'ACROSS' or 'BEYOND.' The prefix 'AERO' is four letters long and means 'AIR' or 'ATMOSPHERE.' The prefix 'DIA' is three letters long and means 'THROUGH' or 'ACROSS.' These prefixes are often used to describe transportation-related activities, such as AIR travel, crossing a border, or going THROUGH a tunnel.