While Affirmative Action was ideally meant to level the playing-field, nowadays, it is an excuse for some high school seniors to not worry about receiving scholarships and other grants for college, or for some to expect promotions at work. Unfortunately, Afrrimative Action has been abused.
In some areas where there is a paucity of minorities, Affirmative Action becomes a method for the insistence that communities hire in their police, fire, and other municipal departments a certain number of minorities, even when their percentages do not reflect the demographics of the city or town.
Thus, Equal Opportunity for All has opened doors for some, but not for all.
In my own words, affirmative action is a policy that seeks to "level the playing field" and give an equal chance to groups that have been systematically and historically discriminated against.
Giving you another perspective of a similar problem outside the US, in India affirmative action is called reservation. Here, for several centuries large portions of the society who belonged to certain castes had faced the same kind of problems that women and the people of color had faced in the US.
Now, in the name of correcting that and providing them an equal chance a certain quota of seats in colleges, government jobs, etc. are reserved for them. Though the objective of doing this does not look wrong, it has become a tool for politicians to gain a larger vote bank. Most implement the reservation irrespective of the current socio-economic situation of the candidate asking for the favor. A large number of people of the earlier higher castes find no opportunity for growth due to the reservations.
If we assume that what #5 states is true, then the government stepping in to safeguard the Rights of those discriminated against soley on the basis of color or ethnicity was a proper function -- the government's job is to safeguard Rights. However, what affirmative action seems to have devolved into was the establishment of hiring quotas, etc., which was not a proper function -- and caused the reverse discrimination phenomenon.
Affirmative Action can be described as the government stepping in to various situations such as employment and admissions and legalising a preferential stance towards groups of Americans who have traditionally been disenfranchised thanks to racism. It can be seen, for example, in the setting of quotas that colleges must achieve in terms of the cultural make-up of their student in-take.
My definition of Affirmative Action is similar to those posted above. I believe that the laws were created so as to prevent discrimination and help people who the nation has historically oppressed.
I agree with Brett and I will just add a bit to explain the origins of the term. There were negative actions that the government had to take to stop harming people of color. In other words, governments had to stop having things like Jim Crow laws. By contrast, affirmative action was supposed to be things that the government could do (rather than stop doing) to help people of color.
I guess my definition of Affirmative Action would be something along these lines: the granting of limited preferences in admissions, contracts and hiring to those groups of Americans who have been historically, and continue to be presently, disadvantaged or discriminated against.