NYQUIL Meaning of NYQUIL in English Ny ‧ quil /ˈnaɪkwəl, ˈnaɪkwɪl/ BrE AmE trademark a type of liquid medicine sold in the US, which reduces pain, helps people stop coughing, and helps them sleep Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012