Dissent Definition:

To disagree.

The word is used in legal circles to refer to the minority opinion of a judge which runs contrary to the conclusions of the majority in a particular judgment.

For example, in Roe v Wade (410 US 113), the well-known 1973 American abortion decision, two of the nine Supreme Court of the United States judges dissented with a clear majority of 7 striking down a Texan anti-abortion statute. The two dissents, while interesting for the record, didn't matter in the result. A majority was all that was needed in a multi-member Court, and full finality was achieved where the Court is a final court of appeal, as is the case with the USA Supreme Court.