may refer to one of the following:
- Hardware description language
- Hard Disk Loader, which is bootting from a hard disk replaced CD/DVD of video games, Japan.
- High density lipoprotein, so-called "good cholesterol".
- Hong-kong Desny Land, in China.
- HDL (NDB), call sign of an non-directional beacon at Plankstadt, Germany.
- Les Hurlements d'Léo, an alternative rock band from France.
- The Halle du Livre, a library in Nancy, France (often abbreviated HdL with the "d" uncapitalised).
- A German abbreviation of "Hab dich lieb", common in informal written communication, meaning "I love you" among friends rather than among lovers (see I love you).