There isn't a single Greek word that directly translates to "today." The way you'd say "today" in Greek depends on the context. Here are a few options:
* σήμερα (símera): This is the most common and generally accepted word for "today."
* αὐτήμερον (aftímeron): This is a more formal or literary option.
So, while there's no perfect equivalent, σήμερα (símera) is the best and most commonly used word.