Post hoc date

When two people in the 'talking phase' meet up initially and do date type things without planning on it, only to later realise that their meeting could qualify as a date.

Post hoc date refers to a date that is officially recognized or labeled as such after the fact, rather than being a planned or intentional first date.

The couple laughed about their first meeting, realizing that it was actually a post hoc date, as they had already grown close through weeks of getting to know each other.