For a finite thin wire of arbitrary form near the ground we generalized the concept of modal parameters for a full-wave transmission-line theory, investigated earlier for lines with high symmetries (straight wire(1,2) and circle wire 3). These parameters are contained in the coupling equations for each mode. They are complex-valued, frequency and gauge dependent, and they depend on the modal number. With the concept of generalized transmission-line (TL) parameters it is shown that a thick wire can be treated as a multiconductor transmission line.