HJ may refer to:
Science, technology, and mathematics
- Hall–Janko group, a mathematical group
- Hamilton–Jacobi equation, an equation in classical mechanics which also has relations to quantum physics
- U.S. code for a cryptographic key change; see cryptoperiod
Other uses
- ⟨hj⟩, a two-letter combination used in some languages
- hj-reduction in English, dropping the /h/ sound before /j/
- Hajji (Hj.), an Islamic honorific
- Handjob
- hic jacet ('here lies'), Latin phrase on gravestones
- Hilal-i-Jurat, post-nominal for Pakistan honour
- Hitler-Jugend (Hitler Youth)
- Holden HJ, an Australian car 1974-1976
- Hot Jupiter, a type of planet
- Tasman Cargo Airlines, IATA airline designator
- Jiaguwen Heji, the standard comprehensive collection of rubbings of ancient Chinese oracle bone inscriptions
- "High jump" athletics abbreviation in track and field
This disambiguation page lists articles associated with the title HJ.If an internal link led you here, you may wish to change the link to point directly to the intended article. Category: