Meaning of SUBSTITUTION in English

SUBSTITUTION

sub ‧ sti ‧ tu ‧ tion AC /ˌsʌbstəˈtjuːʃ ə n, ˌsʌbstɪˈtjuːʃ ə n $ -ˈtuː-/ BrE AmE noun [uncountable and countable]

[ Word Family: noun : ↑ substitute , ↑ substitution ; verb : ↑ substitute ]

when someone or something is replaced by someone or something else, or the person or thing being replaced:

Coach Ross made two substitutions in the second half.

substitution of something for something

the substitution of English for French as the world’s common language

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.