char** or char*** in function arguments?

What does it mean when a function argument contains multiple "*" - for 
example:

/***************************************/
int GetNameData(char*** faceName)
{
	*faceNames = registeredFaceNames;
	return numOffaceNames;
}
/***************************************/

or

/***************************************/
int AreValuesValid(char ** error, double * paramValues)
{
	<statements>
}
/**************************************?

?

I know a single "*" after a type designation makes it a 
"pointer-to-type", but what about multiple "*" (such as  char***  or 
char **  shown above)? What do those do?

Also, so far I've only seen this used with "char" types.  Is this 
something specific to that type only?

Thanks for any help.