The Collaborative International Dictionary of English v.0.48:
Acentric \A*cen"tric\, a. [Gr. 'a priv. + ? a point, a center.] Not centered; without a center. [1913 Webster]WordNet (r) 3.0 (2006):
acentric adj 1: lacking a centromere; "an acentric chromosome fragment" 2: not centered or having no center