The Collaborative International Dictionary of English v.0.48:

Ceterach \Cet"e*rach\, n. [F. c['e]t['e]rac, fr. Ar. shetrak.]
   (Bot.)
   A species of fern with fronds (Asplenium Ceterach).
   [1913 Webster]

WordNet (r) 3.0 (2006):

Ceterach
    n 1: small genus of Old World ferns; superseded in some
         classification systems which place plants of this genus in
         e.g. genera Asplenium and Pleurosorus [syn: Ceterach,
         genus Ceterach]