at the present time or moment.
where are you living now?
used, especially in conversation, to draw attention to a particular statement or point in a narrative.
now, my first impulse was to run away
used in or as a request, instruction, or question, typically to give a slight emphasis to one's words.
now, if you'll excuse me?
used at the end of an ironic question echoing a previous statement.
“Mom says for you to give me some of your stamps.” “Does she now?”