I like how this person describes them, they just forgot to say the 1st house is angular:
Your Angular Houses – 4th, 7th and 10th. These are the engine room of your chart. What rules them and the planets they contain will show the power, passion and drive in your life.
Your Succedent Houses – 2nd, 5th, 8th and 11th. These are the social houses, how you engage with others and the world, for better or for worse! The planets and the house rulers will show how and why you reach out to others. Your Cadent Houses, 3rd, 6th, 9th and 12th these houses reveal what or who you server, your dedication, vocation or sense of duty. The planets in these houses and their rulerships reveal how you deal with these, at times unconscious, commitments.