to lead a community: to go in front of others as their guide and head
In the New Testament this sense always shows up as a participle used like a noun, "the one who leads" or "those who lead." It never appears as a plain finite verb here. That small fact carries weight: the word describes people by what they keep on doing, not by a fixed office they hold. A leader, in this usage, is one who in ongoing practice goes ahead of the group.
The word covers a wide social range. In the wider Greek world it named village headmen, heads of trade guilds, chairmen of local associations, and even Roman provincial governors. The Greek Old Testament had already made it the standard word for the leader God appoints over his people (נגיד), the figure promised in texts about David. So when the New Testament calls church leaders by this term, the language would have sounded both ordinary to Greek ears and rich with biblical echoes of the shepherd-ruler.
The New Testament writers seem to prefer this flexible word over the more technical titles for church office. In Hebrews the leaders are simply those who "spoke the word of God" to the people and who "keep watch over your souls." Jesus redefines the whole idea in Luke: the one who leads is to be like the one who serves.