What does it mean by the term "code of ethics"?

Answer 1

It's a code of regulations that one is to follow, usually set up by an organization, like the AMA, or a group for it's members. It is a way in which they (the organization) feels their members should act and conduct themselves.

Answer 2

In the context of a code adopted by a profession or by a governmental or quasi-governmental organ to regulate that profession, an ethical code may be styled as a code of professional responsibility, which may dispense with difficult issues of what behavior is "ethical".

Some codes of ethics are often promulgated by the (quasi-)governmental agency responsible for licensing a profession. Violations of these codes may be subject to administrative (e.g. loss of license), civil or penal remedies. Other codes can be enforced by the promulgating organization alone; violations of these codes are usually limited to loss of membership in the organization. Other codes are merely advisory and there are no prescribed remedies for violations or even procedures for determining whether a violation even occurred.

A code of ethics is often a formal statement of the organization's values on certain ethical and social issues. Some set out general principles about an organization's beliefs on matters such as quality, employees or the environment. Others set out the procedures to be used in specific ethical situations - such as conflicts of interest or the acceptance of gifts, and delineate the procedures to determine whether a violation of the code of ethics occurred and, if so, what remedies should be imposed. The effectiveness of such codes of ethics depends on the extent to which to management supports them with sanctions and rewards. Violations of a private organization's code of ethics usually can subject the violator to the organization's remedies (in an employment context, this can mean termination of employment; in a membership context, this can mean expulsion). Of course, certain acts that constitute a violation of a code of ethics may also violate a law or regulation and can be punished by the appropriate governmental organ.

They are often not part of any more general theory of ethics but accepted as pragmatic necessities.

Ethical codes are distinct from moral codes that may apply to the culture, education, and religion of a whole society.

Even organizations and communities that may be considered criminal may have their own ethical code of conduct, be it official or unofficial. Examples could be hackers, thieves, or even street gangs.

Answer 3

You have already received several excellent answers. You may wish to look at some ancient antecedents, among them the Code of Hammurabi and the Hippocratic Oath. There are codes of ethics embedded in other masterworks, such as
"On action alone be thy interest,
Never on its fruits.
Let not the fruits of action be thy motive,
Nor be thy attachment to inaction." -- Bhagavad Gita
or
"And thou shall not glean thy vineyard, neither shalt thou glean every grape of thy vineyard; thou shalt leave them for the poor and strangers." -- Bible