Online style guide
- jail
current usage is jail, not gaol
- Jeep
trademark, so capitalise
- Jekyll and Hyde
- jewellery
(American spelling is jewelry)
- jodhpurs
- Johns Hopkins University
in Baltimore, Maryland
- joyride
- joystick
- ju-jitsu
judo is a less aggressive style of self-defence derived from ju-jitsu
- Judgment Day, the Last Judgment
- judgment, judgmental
- judicature, judicial, judiciary
- junior
is shortened to Jr when part of a name, as in Robert Downey Jr. Not 'Jnr' or any other combo.