- jointing sealant
- journal compound
- jugging screen
- jumping
- jumping-up
- junction
- jurassic limestone
- juvenile
- juxtaposition twin
- Kalevian stage
- kampylite
- kaolin
- karri
- karst valley
- Kaufman number
- keep down
- keeper
- keeve
- kelley stopcock
- kelp
- kempas
- keratin
- keratophyre
- kerosolene
- ketene number
- ketolisation
- ketonic bond
- kettle reboiler
- ivory
- jack post
- jack tool
- jack well
- jacked space
- jacketed
- jackknife
- jam
- Japan wax
- jarrah
- jelly
- jelly-like
- jellying
- jerk pump
- jerrican
- jet coal
- jet condenser
- jet mixing
- jewish stone
- jigger
- jobbing
- johnson bar
- joint dip
- joint grease
- joint stock
- jointer
- junk retriever
- jutty
- juvenile gas
- Kainozoic era
- kaonic atom
- kapur
- karaya gum
- karstic
- katogene
- kelly
- kelyphitic structure
- keruing
- keryl
- keto acid
- ketol
- key-step
- kidney
- killed steel
- killing
- killinite
- kiln man
- kimeridge clay
- jet
- jet blower
- jet gun
- jet mixer
- jet perforating
- jet tray
- jetting action
- jettison
- jig
- Job evaluation
- jog
- joint compound
- joint welding
- joiting adhesive
- journal oil
- jug
- juice
- jump mill
- jump-over
- junior observer
- junk
- jurassic period
- juxtaposition
- kalium cell