Trade date
Trade date is the date on which a security trade occurs. A trade done very early or very late falls on the previous or following trade date. This occurs because in the international market a trade conducted in (e.g.) Japanese equities at  in London needs to effectively be considered as the following day for Japanese stock exchange reporting requirements. In London and the US, the settlement period from trade date is 2 days. See also
Settlement date
Spot date
Value date

References

Securities (finance)
Bond valuation
Swaps (finance)
Settlement (finance)