What is mean by Stare Decisis ?

Stare Decisis
[Latin, Let the decision stand.] The policy of courts to abide by or adhere to principles established by decisions in earlier cases.
In the United States and England, the Common Law has traditionally adhered to the precedents of earlier cases as sources of law. This principle, known as stare decisis, distinguishes the common law from civil-law systems, which give great weight to codes of laws and the opinions of scholars explaining them. Under stare decisis, once a court has answered a question, the same question in other cases must elicit the same response from the same court or lower courts in that jurisdiction.
The principle of stare decisis was not always applied with uniform strictness. In medieval England, common-law courts looked to earlier cases for guidance, but they could reject those they considered bad law. Courts also placed less than complete reliance on prior decisions because there was a lack of reliable written reports of cases. Official reports of cases heard in various courts began to appear in the United States in the early 1800s, but semiofficial reports were not produced in England until 1865. When published reports became available, lawyers and judges finally had direct access to cases and could more accurately interpret prior decisions.