fissure


fissure (http://definr.com/fissure)

     n 1: a long narrow depression in a surface [syn: crevice, cranny,
           crack, chap]
     2: a long narrow opening [syn: crack, cleft, crevice, scissure]
     3: (anatomy) a long narrow slit or groove that divides an organ
        into lobes
     v : break into fissures or fine cracks