Oh, my! The "impedance" is a property of any component, antenna, simply anything. A typical impedance has the real and imaginary components, measured in Ohms.
The "characteristic impedance" is a feature of a transmission line. The "characteristic" means that it is defined by line cross-section shape and dimensions. Typical transmission lines have only the real component. For the purpose of connecting RF power and signal sources and tested components (with any impedance), lines have standardized characteristic impedance of e.,g. 50 Ohms, but for certain designs, 60 and 75 Ohms are preferred. Waveguides have other characteristic impedances that vary with frequency but remain real.