Medical Dictionary
Main Entry:
fis·sure Pronunciation:
'fish-&r, Brit also 'fish-yur Function:
noun 1 : a natural cleft between body parts or in thesubstance of an organ: as
a : any of several clefts separating the lobes of the liver
b : any of various clefts between bones or parts of bones in the skull
c : any of the deep clefts of the brain;
especially : one of those located at points of elevation in the walls of the ventricles —compare
SULCUS d : ANTERIOR MEDIANFISSURE; also : POSTERIOR MEDIAN SEPTUM
2 : a break or slit intissue usually at the junction of skin and mucous membrane <fissure of the lip>
3 : a linear developmental imperfection in the enamel of a tooth —fis·sured /'fish-&rd, Brit also 'fish-yurd/ adjective
[fish-er] 
noun, verb, -sured, -sur⋅ing.
ər