- jackrod
- jackroo
- jackscrew
- jackssery
- jacobean
- jacobian
- jacobin
- jacobinic
- jacobinical
- jacobinism
- jacobinize
- jacobite
- jaconet
- jacquard
- jacquard fabric
- jacquard loom
- jacquard paper
- jactation
- jactitation
- jaculiferous
- jacuzzi
- jade
- jade green
- jaded
- jadeite
- jadeitic
- jaeger
- jaffa
- jag
- jagged
- jagged lines
- jagged rock
- jaggery
- jaggies
- jaggy
- jaguar
- jaguarundi
- jail
- jail delivery
- jail-bird
- jailbird
- jailbreak
- jailer
- jain
- jainism
- jake
- jakes
- jalap
- jaloppy
- jalopy
- jalousie
- jalousie window
- jam
- jam session
- jam signal
- jam tight
- jam weld
- jam-free
- jam-jar
- jam-nut
- jam-packed
- jam-up
- jamabalaya
- jamais vu
- jamb
- jamb block
- jamb liner
- jamb lining
- jamb nut
- jamb post
- jamb shaft
- jamb stone
- jamb switch
- jambeau
- jamboree
- james
- jamesian
- jamin effect
- jammed
- jammer
- jammer finder
- jammer oscillator
- jamming
- jamming signal
- jamming station
- jamming transmitter
- jammy
- jampacked
- jan
- jandal
- jane
- janeite
- jangle
- janissary
- janitor
- janitress
- janizari
- janizary
- jansen clause
- jansenism