- nugget gold
- non-wetting
- nonassociated gas
- nongaseous coal
- nonose
- nonownership theory
- nonpolar solvent
- nonproducing well
- nonsoap grease
- nonviscous fluid
- nonyellowing
- norbornadiene
- normal alloy
- normal butane
- normal chain
- normal habitus
- normal heptane
- normal pentane
- normal pressure
- normal salt
- normal synclinorium
- normal wear
- normalized Q
- nornarceine
- nornicotine
- northupite
- notch effect
- noticeable
- nozzle ring
- nuclear charge
- nuclear energy
- nuclear log
- nuclear mass
- nuclear wave
- nucleation rate
- nucleic acid
- nucleophilic
- nucleus crystal
- number plate
- nut coke
- nut union
- nut-oil
- nyatoh
- oak
- oakmoss resin
- Nusselt equation
- nut coal
- nut lock
- oakum
- objective lens
- obscuration
- observation equation
- observation well
- observer
- occluded gas
- occult mineral
- occupational efficiency
- ocean deep
- ochre
- octad
- octagon bar
- octahedral
- octene
- octylene
- odor test
- odorless
- offshoot
- offshore field
- offshore platform
- oil basin
- oil burner
- oil cake
- oil catcher
- oil coke
- oil company
- oil contamination
- oil conversion
- oil cooling
- oil damping
- oil dehydrator
- oil dipper
- oil exploration
- oil exudation
- oil feed
- oil finding
- oil flotation
- oil foggers
- oil ftraction
- oil gage
- oil grade
- oil heating
- oil lubrication
- ocotea oil
- octadecyl
- octagon iron
- octane
- octane rating
- octane requirement
- octavalent
- octet