Easements are legal rights attached to the ownership of the property - for example a right of way or some other legal benefit which the owner of the property enjoys over land not in his ownership. It is in some ways the reverse of a covenant. Your easement over an adjoining property may be written into their deeds in the form of a covenant in your favour although these are not necessarily recorded by the Land Registry. Your solicitor will check into the validity of those which apply to the property you are thinking of buying.