A criminal defense lawyer is a lawyer specializing in the defense of individuals and companies charged with criminal conduct. Criminal defense lawyers can be permanently employed by the various jurisdictions with criminal courts. Such lawyers are often called public defenders. For a much more extensive discussion of criminal defense, see public defender. The terminology is imprecise because each jurisdiction may have different practices with various levels of input from state and federal law or consent decrees. Other jurisdictions use a rotating system of appointments with judges appointing a private practice attorney or firm for each case.

Source:http://en.wikipedia.org/wiki/Criminal_defense_lawyer