Air pressure is greatest at the bottom of the atmosphere which is at the altitude of sea level. As we ascend in the atmosphere by climbing a mountain or by flying in an airplane.
currency
cylinder
decimal
dedicate
defect
defer
deficient
deflect
degenerate
degrade
deliberate
denominator
denote
dense
depress
deprive
derive
detect
detriment
deviate
devise
devote
diagram
oaf
oak
oar
oases
oasis
oat
oath
oatmeal
oats
obedience
obedient
obediently
obese
obesity
obey
obituary
object
objection
objectionable
objective
objectively
objectivity
objector
obligate
obligated
obligation
obligatory
oblige
obliged
obliging
obligingly
oblique
obliterate
obliteration
oblivion
oblivious
oblong
obnoxious
obnoxiously
oboe
obscene
obscenity
obscure
obscurity
observable
observance
observant
observation
observatory
observe
observer
obsess
obsessed
obsession
obsessive
obsessively
obsolescence
obsolete
obstacle
obstetrician
obstetrics
obstinacy
obstinate
obstinately
obstruct
obstruction
obstructive
obtain
obtainable
obtrusive
obtuse
obvious
obviously
occasion
occasional
occasionally
occult
occupancy
occupant
occupation
occupational
occupied
occupy
similar
airplane