There are 12 signs in the zodiac, corresponding to 12 constellations. From Aries to Pisces, each sign encompasses around 30 days. And each sign has a certain vibration to it. Many of our personality traits are subtly influenced by the astrological sign - also knows as the "solar" sign.
Houses, in astrology, are the projections on Earth of the celestial qualities. There are 12 houses, just like there are 12 zodiac signs. Each house plays a certain role, from the first one, the house of you, up to the twelfth house, the house of karmic ties, isolation and all that is hidden.
There's more to astrology than just the solar sign, the sign in which your Sun was at your birth. As a matter of fact, each planet, from the tiny Mercury, up to the remote and cold Pluto plays a certain role, and talk with a certain vibration, based on the sign and house in which it is placed in your natal chart.