Asymmetric Digital Subscriber LineA form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional modem can provide.
ADSL has the distinguishing characteristic that the data can flow faster in one direction than the other, i.e., asymmetrically. Providers usually market ADSL as a service for people to connect to the Internet in a relatively passive mode: able to use the higher speed direction for the "download" from the Internet but not needing to run servers that would require bandwidth in the other direction.