n 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 .
 
    
 
Similar sounding terms:  sec·ond·ary 
 
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