The crossword solution for the term 'prefix with -mance' is 'BRO'. This is a shortened form of the word 'BROTHER', which is derived from the Old English word 'brether'. The prefix '-mance' is often used to refer to a type of performance, such as a dance or a play. Therefore, when combined with the word 'BROTHER', the term 'bromance' is created, which is used to describe a close relationship between two male friends.