In short, a date is a no strings attached, sexual relationship. There are terms like friend with benefits, casual dating and hooking up, which are all pretty close to the word date, but not quite. Though there are no strings attached, yet a date has a romantic connotation, and promise to explore the relationship. And this is a typically western culture, prevailing in North America and the Europe, though some eastern countries are also warming up to it.
There is also kind of a social pressure in the prevailing dating countries to have sex with more partners, to have sex without involving emotions, and so called ‘cool’ one night stands. So dating is kind of an open relationship where the two partners explore each other sexually and emotionally to find if they are a good fit. If everything falls okay, then they go ahead to a deeper, dedicated relationship, else they part ways, without any hard feelings. Now-a-days, casual sex is also being mixed up with dating, defeating its purpose.