This word (cohors) was originally applied to the divisions of the Italian allies in the Roman army, and consisted of 10k infantry of a) 20 cohortes of 420 men each : the cohortes alares, who formed the wings (alae) of the two legions, and b) four select cohortes of 400 men each. The Roman legion numbered ~4k men, and was divided into ten cohortes, each containing three manipuli or six centuriae. Auxiliary troops were later divided into cohortes auxiliariae, which contained either five or ten centuriae.

Those troops stationed in Rome were also numbered by cohortes:

1. The cohortes praetoriae were the imperial bodyguard formed by Augustus, who were first nine, then ten in number. They were once formed of cavalry; later, infantry.
2. Three (and later four) cohortes urbanae, of 1000 men each. They ranked below the bodyguard and out-ranked the legionaries.
3. Seven cohortes vigilum of 1000 men each who formed the night police and fire brigade - one to every two of the 14 regiones.

Cohort should not be used in place of partner (in crime), or in any case where it refers to one person. I'll fight this 'til the end.

All people born during the same year. This is used in psychology studies, to determine where social trends end and where nature begins. For instance, 60 year olds vote more than 20 year olds. Is this because of age or the political and social climate that this groupwas raised in.

In biology, a cohort is a group of organisms, of the same species, which are tracked from their births to their deaths. A cohort is defined by a specific common characteristic of all the individuals; usually, it is that they were all born at roughly the same time. For example, one could use a cohort of all the carp born in one year to track the survivorship of carp as they age.

Co"hort (?), n. [L. cohors, prop. an inclosure: cf. F. cohorte. See Court, n.]

1. Rom. Antiq.

A body of about five or six hundred soldiers; the tenth part of a legion.

2.

Any band or body of warriors.

With him the cohort bright Of watchful cherubim. Milton.

3. Bot.

A natural group of orders of plants, less comprehensive than a class.

 

© Webster 1913.