Mann meaning and definition in german

The normal plural is Männer, which can be used in all contexts and, nowadays, is used exclusively in contexts other than the following.
The unchanged plural Mann is sometimes used after numerals. It means "men" as a measure for size or strength of a group, rather than individuals. For example: Mit drei Mann können wir den Schrank heben – "With three people we can lift the cupboard." Military or police personnel, team members, demonstrators, and the like, are often counted using this unchanged plural. This may actually include women.
The plural Mannen is now rare and poetic. It usually means a group of men, often soldiers, under the command or leadership of somebody, e.g. Cäsars Mannen ("Caesar's men"). It is sometimes heard in sports jargon, e.g. die Mannen von Trainer XY ("coach XY's men").