A property designated as a house in multiple occupation (HMO) is a building, or part of a building, occupied by three or more people living as more than one household.
A household is categorised as either an individual, or a group of people living together who share a connection. This connection might be through marriage, civil partnership or living as a couple, and also includes family relations such as parents, siblings, cousins, uncles, aunts or foster parents. People who live together, but do not share this connection (such as a group of students or adult friends) count as separate households - even though they share an address and facilities.
An HMO can be a shared house, a bed and breakfast, a hostel, or a building split into bedsits (self-contained flats).
With regards to planning permission, see Planning permission for Houses in Multiple Occupation in Canterbury
For information on the minimum requirements for amenities and management duties see the HMO landlords handbook.