They are the same thing.

A musical ensemble that labels itself a “symphony orchestra” is presumably asserting that it has the instrumentation and competence required to play symphonies, and by extension, the other forms of music that fall within the Western classical music tradition that culminated in the symphonic form. “Philharmonic”, on the other hand, does not refer to any specific musical form, but is simply a word derived from Greek that means “love of harmony”. Still, it affirms the same musical tradition that includes symphonies, so one would expect that these orchestras would have similar repertoires.

So, yeah, they’re pretty much the same thing.

There is none really.

No real difference but it helps when you have more than one orchestra in a given location, just like with sport, eg Manchester United Football Club, Manchester City Football Club and the newcomers Football Club United of Manchester.

You know, I don’t understand how this is my Greatest Question….

And my response above is my Greatest Answer! I don’t know what to make of that.