an establishment consisting of a building or complex of buildings where an organization for the promotion of some cause is situated
a custom that for a long time has been an important feature of some group or society; "the institution of marriage"; "the institution of slavery"; "he had become an institution in the theater"
an organization founded and united for a specific purpose
any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter