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verb: to improve what was old or outdated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