n 1  :  the fourth letter of the Greek alphabet - symbol D or d  2  :  any of various things felt to resemble a capital D : esp  :  the triangular terminus of a pattern in a fingerprint formed either by bifurcation of a ridge or by divergence of two ridges that are parallel beyond it  3  :  DELTA WAVE
or  d-  adj 1  :  of or relating to one of four or more closely related chemical substances <the delta chain of hemoglobin>  <d-yohimbine>  - used somewhat arbitrarily to specify ordinal relationship or a particular physical form and esp. one that is allotropic, isomeric, or stereoisomeric (as in d-benzene hexachloride)  2  :  fourth in position in the structure of an organic molecule from a particular group or atom : also  :  having a structure characterized by such a position <d-hydroxy acids>  <d-lactones>  .
 
 
 
Similar sounding terms:  dahll·ite  de·lead  delt  de·lude 
 
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