The noun today has 2 senses (first 2 from tagged texts)
1. (69) today -- (the present time or age; "the world of today"; "today we have computers")
2. (13) today -- (the day that includes the present moment (as opposed to yesterday or tomorrow); "Today is beautiful"; "did you see today's newspaper?")
Overview of adv today
The adv today has 2 senses (first 2 from tagged texts)
1. (23) nowadays, now, today -- (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")
2. (12) today -- (on this day as distinct from yesterday or tomorrow; "I can't meet with you today")