Tribe
Lineage, Group
suffix
When you associate with a certain lineage, you trace yourself back with a group of people. This group of people is your tribe, your lineage, your group.
けい
The reading is the same as what you learned with the kanji, probably because this word gets stuck onto other things to describe tribes and groups.
私、アキバ系のオタッキーな男性に何故か魅力を感じるんだよね。
Somehow I’m attracted to Akihabara style, nerdy men.