A commercial lease -- as opposed to a residential lease -- is a contract between a business and a landlord for the rental of building space. A lease can be for a short term (as little as one month) or long term (up to ten or 15 years), and it can be written or oral (spoken) -- although an oral lease for more than a year will generally not be enforced by a judge after the first year. For more information, read The Commercial Lease: What You Should Know.
If you need legal advice for your business, talk to a lawyer.