We report a study describing the charm quark by a domain-wall fermion (DWF) in lattice quantum chromodynamics (QCD). Our study uses a quenched gauge ensemble with the DBW2 rectangle-improved gauge action at a lattice cutoff of a −1 ∼ 3 GeV. We calculate masses of heavy-light (charmed) and heavy-heavy (charmonium) mesons with spin-parity J P = 0 ∓ and 1 ∓ , leptonic decay constants of the