I would say dating someone means that you and another person are consistently seeing each other in a boyfriend/girlfriend type of manner. I think back in the day, dating was more loosely going on dates with one or many people, but now dating is the pasts equivalent of going steady.

What is the difference between dating and having a boyfriend?

Commitment is the key in a relationship, thats why its a relationship. People commit to stay together and look forward to a future together while dating (mostly) lacks commitment of any sort. The only commitment people may have while theyre dating is to get an ice cream together, after dinner!