sld

SLD is an acronym that can refer to several concepts across different domains. Because it has multiple common meanings, interpretation depends on context.

In internet infrastructure, SLD stands for Second-Level Domain, the portion of a domain name directly to the left of the top-level domain. For example, in "example.com," "example" is the SLD. The SLD is typically registered with a registrar and, together with the TLD, identifies the site in the global DNS. Subdomains such as "blog" or "shop" sit to the left of the SLD to organize services.

In electrical engineering, SLD refers to a Single-Line Diagram, a simplified drawing of a power system. It uses a single conductor to represent three-phase circuits and shows major components such as generators, transformers, breakers, and feeders. SLDs aid planning, operation, and maintenance by clarifying connections and layout.

In education and psychology, SLD commonly stands for Specific Learning Disability, a disorder affecting learning of reading, writing, or mathematics despite average intelligence and adequate instruction.

In some contexts, SLD has been used for Specific Language Disorder, a developmental language impairment not attributable to other conditions. Usage varies and the term is less standardized than the others.

Because SLD has multiple meanings, interpretation relies on context or accompanying definitions.