Player owned organizations in Life is Feudal are generally called as a Guild, but depending on different positions of these guilds in the world, they have different tiers or levels:
Band
Technically is not a guild at all. Just a bunch of players that are trying to start their own fully efficient guild. Band can not participate in global politics by changing their standings towards other guilds. Members of Band can not bear guild titles and guild tags. Band does not own any land claims. Minimum members: 1
Order
A guild without land claims. A group of minimum 10 players that had started a persistent group. Ideal for mercenaries and small guilds that want themselves to be identified in a world. Order can not participate in global politics by changing their standings towards other guilds. Members of Order bear guild titles and guild tags. Order does not own any land claims. Minimum members: 10
Country
A guild with a built monument and thus owning some lands. Country can participate in global politics and change its standings towards other Countries and Kingdoms. Members of Country bear guild titles and guild tags. Minimum members: 10
Kingdom
A country that have accepted at least one Plea for protection (Ally standing). Kingdom works the same way as a country, but have unique set of titles and its political standings automatically applied with all its vassal Countries. In other words Kingdom is a leading guild in an alliance of different guilds. Minimum members: 10 Minimum number of vassal Countries: 1