*in a smug British accent* "Well, you see, my learn-ed friend, the Oxford Dictionary defines 'up' as..

adverb

1. toward a higher place or position. 'he jumped up'
2. at or to a higher level of intensity, volume, or activity. 'she turned the volume up'

preposition

1. from a lower to a higher point on (something); upward along. 'she climbed up a flight of steps'

adjective

1. directed or moving toward a higher place or position. 'the up escalator'
2. at an end. 'his contract was up in three weeks'

noun

1. a period of good fortune or positive mood. 'you can't have ups all the time in football'
2. a pretty good Pixar movie. 'despite its name, Up is underrated'

verb

1. cause (a level or amount) to be increased. 'capacity will be upped by 70 percent next year'
2. lift (something) up. 'everybody was cheering and upping their glasses'
   

That, good *sir*, is what 'up' is!"

*ungodly smug chuckling accompanied by excessive monocle adjustment and eyebrow wiggling*