Subculture
From Memory Alpha, the free Star Trek reference
A subculture was a subdivision of a culture where people practiced their own customs and traditions. Melders were considered an undesirable subculture by 22nd century Vulcans. (ENT: "Stigma")
While not specifically referred to as such, other subcultures could be seen in Star Trek, most notably the Hippie and punk subcultures on Earth. Sevrin's movement might also be an example. An alien example would be the gender-preferring faction of J'naii.
