Cantofish: lit. different mouths, same voice (idiom); to speak in unison; unanimous
MDBG: different mouths, same voice; to speak in unison (idiom)
LDC:
CDict: (phr) with one voice; (say) in unison'
Click icons for complete source definitions (not available on mobile). icon in each entry gives source attribution. Want to improve this definition? Check to see if 异口同声 is already in CC-CEDICT. If not, you can add it. (Why?)