An inequality is a difference perceived as an unfair distribution of social resources (resource in the broadest sense, including all possibilities of human action: political, economic, cultural, social, sexual, etc..) after an action perceived as social and not as a product of individual personal history.
There is necessarily objective differences of access to resources, because of their rarity. But it takes longer for these differences are perceived as inequality: we need a notion of injustice, a questioning of the legitimacy of the method of selecting those who will be elected, even of their very existence. Inequality may therefore appear (and disappear), not by changing the situation, but by changing the standard of reference. Changes in the subjective value given to the resource may have the same effect.
Inequality and democratic society
The inequalities are based on an objective fact: the socially hierarchical and unequal access among social groups over scarce, and thus desired, resources. However, inequality also have a subjective dimension: they really exist in society if they are perceived by individuals, if individuals regard as unjust a differential access to scarce resources. Thus the social inequality between the sexes or social inequalities based on racist thought, almost naturalized so far, have gradually been perceived as arbitrary, as not being based on any real reason. They have since been denounced as unfair. Inequality is also a subjective fact, the actors represent inequalities, perceive the or not, qualified them as acceptable or outrageous, give them a sense.
Inequality and wealth distribution
The distribution of wealth in society is rarely equal. It can lead to inequalities of income and wealth, some of which are socially accepted (by social justice) and some less. This criterion of wealth is even more relevant to estimate the social scale that society is more “commercial”, but other aspects are also predominating: prestige, status, power, social status, (belonging to the “party”) number and rank of allies.