House
One of twelve divisions of the sky, counted from the eastern horizon at birth. Houses tie a chart to its hour and place, and each one hosts a set of life matters: money, work, partners, home.
Houses divide the local sky into twelve sectors, starting from the Ascendant on the eastern horizon. Unlike signs, which belong to the zodiac and move with the year, houses belong to the horizon and move with the day: the whole framework turns once every 24 hours.
Each house covers a department of life. The first is self and appearance, the fourth home and family, the seventh partnership, the tenth career and public standing, and so on around the wheel. A planet's house shows where its business tends to play out, which is often the most concrete thing a chart says.
Because the wheel turns so fast, houses demand a birth time. A date alone still gives you planets in signs and aspects, which is plenty, but planets in houses would be a guess. And exactly where one house ends and the next begins is a genuine methodological argument: see house system.