If that's an accurate definition, then it's safe to say it would technically mean same day.
Simultaneously, if we want to be technically accurate to a pedantic level, "instant" would be impossible given speed limits of information transmission (speed of light), etc. So "T+0" couldn't mean "instant" in any case.
Maybe some settlements are, in fact, near-instant but I don't think that's implied by "T+0".
> 'T' is the transaction date
If that's an accurate definition, then it's safe to say it would technically mean same day.
Simultaneously, if we want to be technically accurate to a pedantic level, "instant" would be impossible given speed limits of information transmission (speed of light), etc. So "T+0" couldn't mean "instant" in any case.
Maybe some settlements are, in fact, near-instant but I don't think that's implied by "T+0".
[0] https://www.investopedia.com/ask/answers/what-do-t1-t2-and-t...