for·ma·tion 
/foɚˈmeɪʃən/ noun
plural for·ma·tions /foɚˈmeɪʃən/ noun 1 [noncount] : the act of forming or creating something
▪ the formation [=development] of new ideas ▪ The book explains the formation of the planets. 2 [count] : something that is formed or created
▪ an interesting cloud formation ▪ new word formations ▪ rock formations 3 : an orderly arrangement or group of people, ships, or airplanes — often used after in [noncount] ▪ The soldiers were marching in formation. ▪ jets flying in formation [count] ▪ The team ran on the field and lined up in a punt formation.
▪ the formation [=development] of new ideas ▪ The book explains the formation of the planets.
▪ an interesting cloud formation ▪ new word formations ▪ rock formations
