Definition of "Upgrade" :
noun: the act of improving something (especially machinery) by raising it to a higher grade (as by adding or replacing components)
"The power plant received a new upgrade."
noun: hardware that provides better performance than an earlier version did
noun: the property possessed by a slope or surface that rises
noun: a reservation that is improved
"I got an upgrade to first class when coach class was full."
noun: software that provides better performance than an earlier version did
noun: an upward slope or grade (as in a road)
verb: to improve what was old or outdated
"I've upgraded my computer so I can run better software."
verb: give better travel conditions to
"The airline upgraded me when I arrived late and Coach Class was full."
verb: get better travel conditions
"I upgraded to First Class when Coach Class was overbooked."
verb: rate higher; raise in value or esteem
verb: give a promotion to or assign to a higher position