Liveaboard means that you will Live on board of a vessel during your trip.
It is very common, on a diving holiday, to stay on a hotel or resort, and then do day trips for diving. Normally that would involve the transfer to the pier, taking the boat out to the dive site, spend the day onboard and then return to your hotel.
The magic of Liveaboard is that they resolve the diving, the accommodation and the meals all at once, on board. Additionally, while doing a liveaboard , you can access to dive sites that might not be accessible due to distance in a day trip. Long travel crossings are usually done at nigh, while you sleep, so when you wake up, you are ready to dive a great dive site!
Liveaboard is definitively the best way to travel and focus in diving.
During those trips we normally do 4 dives per day.