Probate is a court-supervised process used to validate your will and distribute your property. The process takes anywhere from six months to three years, and may require that lawyers or other professionals be hired. Even if you die without a will, if your estate's value exceeds a threshold amount, your property will still go through probate. In such cases, the court decides how to distribute your estate among your relatives.
A living trust can help you avoid probate. If your assets are placed in a trust, you do not "own" the assets; the trustee of the trust does. You control the assets as if they were yours. When you die, you do not "own" the trust property. Therefore, the trust property does not have to go through probate.