Noun
1. an arrangement of people or things acting as a unit;
"a defensive formation""a formation of planes"2. a particular spatial arrangement
3. the fabrication of something in a particular shape
4. the act of forming something;
"the constitution of a PTA group last year""it was the establishment of his reputation""he still remembers the organization of the club"5. (geology) the geological features of the earth
6. natural process that causes something to form;
"the formation of gas in the intestine""the formation of crystals""the formation of pseudopods"7. creation by mental activity;
"the formation of sentences""the formation of memories"