Main Entry: sig·na·ture

Pronunciation: \ˈsig-nə-ˌchu̇(ə)r, -chər, -ˌt(y)u̇(ə)r\

Function: noun

1 : a feature in the appearance or qualities of a natural object formerly held to indicate its utility in medicine either because of a fancied resemblance to a body part (as a heart-shaped leaf indicating utility in heart disease) or because of a presumed relation to some phase of a disease (as the prickly nature of thistle indicating utility in case of a stitch in the side)
2 : the part of a medical prescription which contains the directions to the patient