cohort

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A group or band of people.
2. n. A companion or associate.
3. n. A generational group as defined in demographics, statistics, or market research: "The cohort of people aged 30 to 39 . . . were more conservative” ( American Demographics).
4. n. One of the 10 divisions of a Roman legion, consisting of 300 to 600 men.
5. n. A group of soldiers.

Century Dictionary and Cyclopedia

1. n. In Roman antiquity, an infantry division of the legion, instituted as a regular body by Marius, though the name was used before his time with a less definite Signification. Its original strength was 300 men, but, the cohort becoming the tactical unit of the army, the effective number was raised almost immediately to 500, or perhaps to 600, and remained practically the same until the end of the empire. The name was also given to bodies of auxiliary troops of the same strength, not necessarily organized into legions, and distinguished either according to nationality or according to their arm, as cohortes funditorum, the slingers; cohortes sagittariorum, the bowmen. See legion.
2. n. Hence A band or body of warriors in general.
3. n. In some systems of botanical and zoölogical classification, a large group of no definitely fixed grade. In zoölogy it is usually intermediate between a family and an order; in botany it is usually a grade next higher than an order, but inferior to a class. Alliance has been used in the botanical sense.

Wiktionary

1. n. A group of people supporting the same thing or person.
2. n. statistics A demographic grouping of people, especially those in a defined age group, or having a common characteristic.
3. n. military, history Any division of a Roman legion, normally of about 500 men.
4. n. An accomplice; abettor; associate.
5. n. Any band or body of warriors.
6. n. botany A natural group of orders of plants, less comprehensive than a class.
7. n. A colleague.

GNU Webster's 1913

1. n. (Rom. Antiq.) A body of about five or six hundred soldiers; the tenth part of a legion.
2. n. Any band or body of warriors.
3. n. (Bot.) A natural group of orders of plants, less comprehensive than a class.

WordNet 3.0

1. n. a band of warriors (originally a unit of a Roman Legion)
2. n. a group of people having approximately the same age
3. n. a company of companions or supporters