The Collaborative International Dictionary of English v.0.48:
Violoncellist \Vi`o*lon*cel"list\, n. [Cf. F. violoncelliste, It. violoncellista.] A player on the violoncello. [1913 Webster]WordNet (r) 3.0 (2006):
violoncellist n 1: someone who plays a violoncello [syn: cellist, violoncellist]