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ptosis
pto·sis [ tṓssiss ] (plural pto·ses [ tṓ sz ])


noun 
Definition:
 
drooping of eyelid: a drooping of the upper eyelid, resulting from muscle weakness or an inability to move muscles
[Mid-18th century. < Greek ptōsis "a falling" < piptein "to fall"]
Encarta® World English Dictionary [North American Edition] © & (P)2009 Microsoft Corporation. All rights reserved. Developed for Microsoft by Bloomsbury Publishing Plc.
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