Terms starting with X

One of the two human sex chromosomes, whose pairing (XX for females, XY for males) determines an individual's sex. See also Y chromosome.

A group of drugs, related to amphetamines and cocaine, that act as central nervous system (CNS) stimulants; caffeine is a common example.

An institution established during the reign of Roman Emperor Constantine (288-337) to provide temporary food and shelter for those who were destitute or infirm.

Persistent, intense, and unreasonable fear of strangers or foreign people.

Chinese term for filial piety, or loyalty to one's kin, a central value among Chinese families. Xiao is manifested most notably in caring for one's elderly or i…