social groups that are in a disadvantaged or vulnerable position, such as those with low income, limited education, or disabilities; the economically and politically marginalized

(statistics) the entire group being studied; parent population

a small group of people within a larger society or organization; a microcommunity

Resistance to the spread of an infectious disease within a population that is based on the pre-existing immunity of a high proportion of individuals.

mass incident; a term used in the mainland to describe incidents of social unrest such as protests, strikes, and riots that threaten social stability

A group of people organized through specific social relationships and shared activities who develop a collective consciousness; examples include groups based on kinship, geography, or profession.