Everybody understands the substantive Mann as designating a male human individual.
Some people might also be aware of the kinship between Mann and the verb to command, which crops up for instance in the Old Swedish noun mander.
I have had however a few suspicion that the Mann substantive also could be interpreted collectively as a tribe.
- The Alemanni confederation of tribes who became notorious in Roman Gaul during the Late Roman empire and its collapse, which yielded so many ethnonyms for the German people (e.g. "Les Allemands", "Los Alemanes" to name but a few). In this occurrence it seems that "Alle Männer" must be be understood as "all tribes" rather than "all men".
- The etymology of the ethnonym the Normans. In old English, you have "Norðmann", a precise translation of which would be the "people from the North" as in "Nordleuten" rather than "men from the North" "Nordmänner"1.
- The kinship mentioned above between Mann (a concept related to a single individual) and to command2 (a concept related to a troop, a clan or a party).
- So I'm curious to know whether there are some more indications of an old phased out meaning of Mann as a tribe rather than a single individual.
- Considering that in many of today's nomadic people there are clear indications that a tribe is little more than an extended family, would that be a possible explanation.
 Late edit. I quote the "Norðmann" word on the premises that Old English is part of the West Germanic subfamily of Germanic languages. Although both Normannen in German and Norman in English are later loanwords from Old French (11c.), the word Norðmann is endemic to Old English and its use attested in various Wessex manuscripts (10c. also Normann).