When executing a lease, tenants and property owners agree who will pay for various operating, nonoperating, and capital expenses. Such agreements usually take one of the common patterns summarized as follows:

Gross (full service) leases
Tenant pays rent only; property owner provides or pays for all services (like cleaning...), operating expenses (like utilities...), nonoperating expenses (like property taxes and insurance costs...) and capital outlays (for things like repairs...)
Modified (full service) leases
Tenant pays rent AND may pay some direct pass throughs of operating expenses (like electricity...) where usage varies by tenant and can be submetered.
AND tenant may pay pass throughs for nonoperating expenses (like property taxes and insurance costs...) which are out of the control of the property owner.
Leases with Operating Expense Recoveries
Tenant pays rent AND reimburses property owner for agreed upon "recoverable expenses" based on agreed upon recover structures (like expense stops...)
Leases where Tenants Pay Expenses Directly
- Single Net Leases
  Tenant pays rent and pays for all operating expenses identified in the lease
- Double Net Leases
  Tenant pays operating expenses AND nonoperating expenses such as property taxes and insurance costs
- Triple Net Leases
  Tenant pays operating, nonoperating, AND certain recurring capital outlays for repairs, alterations, and modifications of the interior and possibly even the exterior of the property.

From Brueggeman & Fisher, Real Estate Finance & Investments, Seventeenth Edition, pp265-267