tomorrow

I. to‧mor‧row¹ S1 W2 /təˈmɒrəʊ $ -ˈmɔːroʊ, -ˈmɑː-/ BrE AmE adverb
[Language: Old English; Origin: to morgen, from to 'to' + morgen 'morning']
on or during the day after today ⇨ yesterday, today:
Our class is going to London tomorrow.
a week from tomorrow (also a week tomorrow/tomorrow week )British English:
Terry’s new job starts a week tomorrow.
tomorrow morning/night etc
We’re meeting tomorrow evening.

Oxford Advanced Learner's Dictionary

tomorrow

to·mor·row [tomorrow tomorrows] adverb, noun [təˈmɒrəʊ] [təˈmɔːroʊ] [təˈmɑːroʊ]

adverb
on or during the day after today
• I'm off now. See you tomorrow.
• She's leaving tomorrow.
• (especially BrE) They arrive a week tomorrow/tomorrow week (= after a week, starting from tomorrow).
see jam tomorrow at jam _n.
Word Origin:
Middle English (as two words): from the preposition to + morrow. Compare with today and tonight.

Idiom: do something as if there's no tomorrow

Cambridge Advanced Learner's Dictionary

tomorrow / təˈmɒr.əʊ / / -ˈmɔːr.oʊ / adverb , noun [ U ]

A1 (on) the day after today:

I've arranged to see Rachel tomorrow night.

Oh, leave it till tomorrow.

Is John coming to tomorrow's meeting?

He'll be back tomorrow week /a week tomorrow (= a week from tomorrow) .

C2 used more generally to mean the future:

Today's problem child may be tomorrow's criminal.

We make sacrifices now to give our children a better tomorrow.

Collins Advanced Learner’s English Dictionary

tomorrow

[təmɒ̱roʊ, AM -mɔ͟ːr-]
tomorrows
1) ADV: ADV with cl You use tomorrow to refer to the day after today.
  Bye, see you tomorrow...
  The first official results will be announced tomorrow.
N-UNCOUNT
Tomorrow is also a noun. What's on your agenda for tomorrow?... Davies plays for the Barbarians in tomorrow's match against England... Tomorrow is Christmas Day.
2) ADV: ADV with cl You can refer to the future, especially the near future, as tomorrow.
  What is education going to look like tomorrow?
N-UNCOUNT: also N in pl
Tomorrow is also a noun. ...tomorrow's computer industry... Experiences in the past become a part of us, affecting our tomorrows.

Merriam-Webster's Advanced Learner's Dictionary

²tomorrow adv : on, during, or for the day after today
• I'll finish the housework tomorrow.
• Is it supposed to rain tomorrow?
• He has an interview tomorrow.
• Tomorrow we're going fishing.