NNN————NNN lease，网上抄来的

In United States real estate business, "net lease" is a term used for an arrangement in which the tenant or lessee is responsible for paying, in addition to base rent, some or all of the expenses related to real-estate ownership. These expenses, often called the "three nets", are property taxes, insurance, and maintenance. Because the rent collected under a net lease is net of expenses, it tends to be lower than rent charged under a gross lease. Net lease types include single net, double net, and triple net leases, with the term "net lease" often being used as a shorthand expression for any of these arrangements. A triple net lease (i.e., one that is net of all three of the major expense categories) is often abbreviated as "NNN lease", but is still pronounced as "triple net lease".