there·by 
/ðeɚˈbaɪ/ adverb
/ðeɚˈbaɪ/ adverb formal : by means of that act, those words, that document, etc.
▪ He signed the contract, thereby forfeiting his right to the property.
▪ He signed the contract, thereby forfeiting his right to the property.
thereby hangs a tale — see 1hang
