lept(o)-

Small; narrow.

Greek leptos, fine, thin, delicate.

This form appears in a variety of terms in the sciences: leptin is a protein produced by fatty tissue which regulates fat storage in the body; a lepton is a small subatomic particle, such as an electron or muon, which does not take part in the strong interaction; leptospirosis (Greek speira, coil, from the shape of the bacterium) is an infectious bacterial disease in animals that can be transmitted to humans as Weil's disease; the leptomeninges are the inner two layers that cover the brain and spinal cord, between which the cerebrospinal fluid circulates; in statistics, a frequency distribution that is leptokurtic (Greek kurtos, bulging) is concentrated about the mean.