- isotropic material
- isotropic thickness gauge
- issue slip
- iteration
- iterative phase constant
- izett steel
- jack arm
- jack pad
- jack switch
- jackbox
- jackengine
- jacket tube
- jacketed intake pipe
- jacking of pile
- jacklamp
- jackshaft
- jacl hammer drill
- jacquets method
- jagged
- jam bar
- jamb cleaner
- jamming coverage
- janney pump
- jar mill
- jarring mark
- jato unit
- jaw gage
- jaw plate
- jazz the motor
- jelly
- jenny scaffold
- jessop
- jet analyzer
- jet blade
- jet chimney
- jet crop drier
- jet dryers sizing machine
- jet flow
- jet head
- jet leaching
- jet noise
- jet piercing method
- jet presure
- jet propulsive efficiency
- jet relay
- jet starter
- jet thrust reverser
- jet vane
- jetexhaust
- jettisonable auxiliary fuel tank