lidocaine UK /ˈlɪd.ə(ʊ).keɪn/US /ˈlaɪ.dəˌkeɪn/ noun1 •A crystalline compound, C₁₄H₂₂N₂O, that is used in the form of its hydrochloride as a local anesthetic and as an antiarrhythmic agent.In addition, 0.5 ml of 1% lidocaine HCl was injected subcutaneously in the postauricular area for local anesthesia. — 2015 formslidocaines