Troeltsch distinguished between these.
1. Churches are large, with millions of members, place few demands on members, have a bureaucratic hierarchy, claim a monopoly of truth and are universalistic, ideologically conservative and linked to the state.
2. Sects are small, exclusive groups demanding real commitment from members, are hostile to wider society, recruit from the poor and oppressed, often have charismatic leadership and believe they have a religious monopoly of truth.