Definition of up:

part of speech: interjection

Arise; raise up.

part of speech: preposition

From a lower place or position to a higher; not down.

part of speech: adverb

Aloft; on high; in a state of advance; in a state of being raised or increased; in a state of climbing or ascending; in a state of insurrection; in a state of elevation; out of bed; into order, as he drew up his company; much used in modifying the action of a verb.