a generic name for digital lines that are provided by telephone companies to their local subscribers and that carry data at high speeds
"The internet connection in my apartment relies on DSL, which uses the existing phone line to deliver fast data speeds."
Initialism of domain-specific language.
"The compiler team decided to develop a new DSL to handle complex financial calculations more efficiently than general-purpose code."
In plain English: DSL is an internet connection that uses your phone's copper wires to send data faster than old dial-up speeds.
"My internet connection was slow until I switched to dsl service."