today

nouns

the present time or age
"the world of today"; "today we have computers"
today
is a type of (narrower)
the period of time that is happening now; any continuous stretch of time including the moment of speech
"that is enough for the present"; "he lives in the present with no thought of tomorrow"
nowadays, present
the day that includes the present moment (as opposed to yesterday or tomorrow)
"Today is beautiful"; "did you see today's newspaper?"
today
is a type of (narrower)
time for Earth to make a complete rotation on its axis
"two days later they left"; "they put on two performances every day"; "there are 30,000 passengers per day"
24-hour interval, day, mean solar day, solar day, twenty-four hour period, twenty-four hours

adverbs

in these times
"it is solely by their language that the upper classes nowadays are distinguished"- Nancy Mitford; "we now rarely see horse-drawn vehicles on city streets"; "today almost every home has television"
now, nowadays, today
on this day as distinct from yesterday or tomorrow
"I can't meet with you today"
today