now
I
 /ˈnaʊ/  adv  
  1 : at the present time
   We were having trouble before, but everything's okay now.
   I'm feeling much better now, thank you.
   I love you now and I'll love you forever.
   Now's the time for action.
   “And now,” he said, “all we have to do is wait.”
   “Can we talk?” “Not now. I'm really busy.”
   The room is now used as a home office. = They now use the room as a home office.
   He knows now that he was wrong.
   Police have now identified the man who they believe stole the car.
   Scientists now believe that the bones belong to a different species of reptile.
   the now famous photograph of an American sailor kissing his young wife
   I wish I knew then what I know now.
   This is the only chance you'll ever get. It's now or never.
  — often used to show that you are annoyed about something
   Now you tell me?! I needed to know that yesterday!
   You tracked dirt everywhere! Now I have to spend all day cleaning again!
   “I know you've explained a lot–but can I ask just one more question?” “What now?” = “What is it now?” = “Now what?”
   OK: I'll do it your way. Are you happy now?
  2 : in the next moment : very soon
   I have to leave now. [=right now, right away, immediately]
   It's time to go home now.
   If I don't do it now, I'll forget to do it later.
   They'll be back any minute now!
   Any day now, he'll be walking through that door.
   Now which way do we go?
   What do I do now?
   What now? = Now what? [=what next?]
  3 : in the present situation
   He'll never believe me now!
   If you can't stand the heat now, you certainly won't be able to stand it in the summer.
  4 : at the time referred to in the past
   Her parents arrived home the next day. Now the trouble really began.
   I next met her again a few years later. She was now 30 years old and working for a law firm.
  5 : for an amount of time until the present time
   It's been several years now since I last saw her. [=I haven't seen her for several years]
  — often used with for
   We've lived here for a long time now. = We've lived here for some time now.
   She has been teaching for 20 years now. = She has been teaching now for 20 years.
  6
  — used to make a command or request or to express criticism or disapproval
   Hurry up, now, class started three minutes ago.
   Now, Billy, that's no way to talk to your mother!
   Now you be sure to write, you hear?
   Well, now, what is this I hear about you going back to school?
   Come now. You know that's not true. = (chiefly US) Come on, now. You know that's not true.
   Now, which one of you kids broke the window?
   Now, you listen to me.
   Now see here!
  7
  — used to introduce an important idea or to show a change in subject
   Now, I'd like to call your attention to the statue in the middle of the room.
   “What's the meaning of life?” “Now that's what I call a really important question!”
   Now that was a great song!
   Now where was I? Oh yes, I was telling you about my Uncle Harry.
   Now you've done it!
   Now don't get too excited.
   Now who could that be?
   Now then, what shall we do next?
  ◇ The phrase now for is often used to introduce a different idea or activity.
   That was an easy question. Now for something a bit more challenging.
   Now for today's top news stories.
  8 literary : at one moment : sometimes
   now one and now another
   She was now laughing, now crying.
  even now — see even, 2
  (every) now and then ( also   (every) now and again)
   : not often but sometimes
    We still see each other (every) now and then.
    Now and then she would come in to check on me.
    The silence in the house was broken now and again by the ringing of the telephone.
  just now — see just, 2
  now, now
   1
    — used to tell someone not to be worried or unhappy
    Now, now, don't cry. Everything will be all right. You'll see!
   
   2
    — used to express criticism or disapproval
    Now, now. There's no need to use that kind of language.
   
  now you're talking — see talk, 1
  right now — see right, 2
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II
  conj  
  : since something is true : because of the fact that something happened
   Now you mention it, I am kind of hungry.
  — usually + that
   Now that you mention it, I am kind of hungry.
   Now that we're all here, let's start the meeting. = Let's start the meeting now that everyone's here.
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III
  noun   [  singular  ]
  : the present time or moment
   A lot of things can happen between now and then.
   By now, you must have heard the news. = You must have heard the news by now.
   The kids are supposed to be in bed by now.
   That's enough for now, but we may need some more later.
   Things are fine for now.
   Fifty years from now you'll be telling your grandchildren about this day.
   She's due back a week from now.
   We'll be here from now until November.
   I promise, from now on [=from this moment and forever into the future], I'll always tell you the truth.
   From now on, no one can use my car without my permission.
   Until now, doctors had no idea what caused the disease. = Up to now, they didn't know what caused it.
  — see also here and now at here, 1