These words, as here considered, refer to groupings in, or divisions of, a stratified society. Class is the most general word. It refers primarily to a social division of society, as the middle class ; but a class may also be an economic division, as the working class , a functional division, as the managerial class ; or a division embracing persons with other common characteristics, as the educated class . Classes are based on such things as lineage, income and occupation. A caste , by contrast, is a strictly hereditary division of society ?especially one of the four Hindu social classes in India. The highest of these is the Brahman, or priestly, caste . A member of the lowest caste was formerly called an untouchable, his touch having been counted as pollution by Hindus of higher station. A person is able to move from one class to another; but where a rigid caste system is in effect, he cannot escape from his caste .

An estate is a class of people with a distinct political or social status, having in common special duties, privileges, powers or limitations with respect to government. An estate was originally one of the three classes of feudal society in Europe ?the Estates of the Realm being the clergy, the nobility, and the common people. The political power of the press later caused the journalistic fraternity to be dubbed the fourth estate . In a general sense, estate, like class , may be used to indicate rank, position or social standing: a lady of high estate . Class is also applied to thing or services as a measure of quality: first-class as opposed to tourist-class accommodation.

In one sense, order is close to class in indicating a stratum of society or a cohesive social or professional group: the scorn of the aristocracy for the lower orders. Specifically, order often refers to the rank or position of an ordained Christian clergyman ?a bishop being in the highest order of the ministry, a priest in the second, and a deacon in the third. In traditional angelology, order designates one of the nine grades or choirs of angels, which are, in ascending rank, angels, archangels, principalities, powers, virtues, dominations or dominions, thrones, cherubim and seraphim. Order may also refer to an honorary society to which members are named by a sovereign as a mark of the highest distinction: The Order of the Garter is the highest order of knighthood in Britain.