Is a galvanic cell only called that if copper and zinc are used? I know other metals can be used to get the same effect but I'm interested in the name. Is it only called a galvanic cell if copper and zinc are used? Or is the name "voltaic cell" used only when copper and zinc are used? I'm confused because I've heard them being used interchangeably.
Voltaic cell and galvanic cell are both synonyms for the same thing: An electrochemical cell, which produces an external electric current. So the two terms can be used interchangeably.

Check out also a site from Georgia state University, where it says:


  Electrochemical cells which generate an electric current are called voltaic cells or galvanic cells, and common batteries consist of one or more such cells.




Addendum: Nevertheless there might be some galvanic cells, like the Daniell Cell, which have a defined electrode material and defined electrolyte concentrations to supply a specific voltage.

For the Daniell cell these would be:

$$\begin{array}{lc}
\text{Electrode material:} &amp; \ce{Zn|Zn^{2+}||Cu^{2+}|Cu}\\
\text{Electrolyte concentrations:} &amp; c(\ce{Zn^{2+}}) = c(\ce{Cu^{2+}}) = 1\ \mathrm{mol\ l^{-1}}\\
\text{Voltage:} &amp; U(25\ \mathrm{°C}) = 1.10\ \mathrm{V}
\end{array}$$