domaine de second niveau(A domain name that is rooted hierarchically at the second tier of the domain namespace directly beneath the top-level domain name such as .com and .org. When DNS is used on the Internet, second-level domains are names such as microsoft.com that are registered and delegated to individual organizations and businesses according to their top-level classification. The organization then assumes further responsibility for parenting management and growth of its name into additional subdomains)
