How to start a startup

This word startup has attracted so many, it's not just limited to the young generation but the Suite executives as well. It has been a trend that the executives between ages 35 to 45 have been quitting their current cooperate jobs and are putting in efforts to think about initiating their own Startups or work with a startup from the most uncomfortable places or locations. Many giant corporations have also stepped up a different division which is into acquiring the startups and deploying a suite team to work on that startup. The government of various countries irrespective of whether they are developed or developing. They have launched startup schemes which focuses on supporting and helping the under resource startups to work aggressively on their idea and grow rapidly. 

So what is this startup really and how to really start one? Why did this word startup catch the attention of masses?