The Collaborative International Dictionary of English v.0.48:

Tetter \Tet"ter\, n. [OE. teter, AS. teter, tetr; akin to G.
   zitter, zittermal, OHG. zittaroch, Skr. dadru, dadruka, a
   sort of skin disease. [root]63, 240.] (Med.)
   A vesicular disease of the skin; herpes. See Herpes.
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   Honeycomb tetter (Med.), favus.

   Moist tetter (Med.), eczema.

   Scaly tetter (Med.), psoriasis.

   Tetter berry (Bot.), the white bryony.
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