Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «N»:
Nyctophobia: Pathological fear of the dark, an abnormal and
persistent dread of the dark. Sufferers experience anxiety even
though they may rationally realize that the dark does not pose a
threat commensurate with their fear.
Formed from the Greek "nyx" (night) and the Greek "phobos"
Nymph: A nymph is a stage in the life cycle of certain arthropods, as ticks and lice. (Not all nymphs are in Greek mythology.)
There are three stages in the life cycle of lice: the nit, the nymph, and the adult. The nymph stage comes between a nit and an adult louse.
Nits are lice eggs. They are ha...
Nystagmus: Rapid rhythmic repetitious involuntary (unwilled) eye
movements. Nystagmus can be horizontal, vertical or rotary....