noun
or syn·aes·the·sia ˌsinə̇sˈthēzh(ē)ə
Etymology: New Latin, from syn- + -esthesia, -aesthesia (as in anesthesia, anaesthesia )
: a concomitant sensation ; especially : a subjective sensation or image of a sense (as of color) other than the one (as of sound) being stimulated — compare chromesthesia , phonism , photism