Lacrimation or lachrymation (lacrima = tear) is the production
or shedding of tears. Tears are secretions that clean and lubricate
the eyes.
There are 3 types of tears:
Basal tears lubricate the eye and keep it clear of dust.
Reflex tears result from irritation or the eye by foreign
particles or vapors.
Psychic tears are produced by some type of strong emotional
stress.