The black part of the eye through which light enters, it enlarges in dim light and decreases in size in bright light.

Changes to pupil size can also be triggered by emotional responses to stimuli, which can be monitored and interpretted as subtle visual clues to how one person reacts to another.

Mind or body altering substances/intoxicants can cause a pupil's reaction to light to differ from that of a non-intoxicated individual, with varied different abnormal responses, which also can be monitored and interpretted as visual clues of what a person is under the influence of.

Pu"pil (?), n. [F. pupille, n. fem., L. pupilla the pupil of the eye, originally dim. of pupa a girl. See Puppet, and cf. Pupil a scholar.] Anat.

The aperture in the iris; the sight, apple, or black of the eye. See the Note under Eye, and Iris.

Pin-hole pupil Med., the pupil of the eye when so contracted (as it sometimes is in typhus, or opium poisoning) as to resemble a pin hole.



© Webster 1913.

Pu"pil, n. [F. pupille, n. masc. & fem., L. pupillus, pupilla, dim. of pupus boy, pupa girl. See Puppet, and cf. Pupil of the eye.]


A youth or scholar of either sex under the care of an instructor or tutor.

Too far in years to be a pupil now. Shak.

Tutors should behave reverently before their pupils. L'Estrange.


A person under a guardian; a ward.


3. CivilLaw

A boy or a girl under the age of puberty, that is, under fourteen if a male, and under twelve if a female.

Syn. -- Learner; disciple; tyro. -- See Scholar.


© Webster 1913.

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