Both terms are frequently used incorrectly, and I don't believe that PRS uses coil taps in their regular HB equipped guitars (except for the 408 equipped guitars and maybe the 513).
As said, a coil split is cutting off one coil of a humbucker completely, so you're left with one coil active.
Coil tapping involves an additional wire (or 2) connected to the windings of the pickup coil/s, so you can "tap in" to the windings at that point.
PRS up until about 2010(?) used plain ol' coil splits, where they would ground the split wire with a switch, shorting one coil to ground, and leaving one coil active (path of least resistance). They then started doing "the resistor mod", which involves putting a resistor (1.1k neck, 2.2k bridge) between the switch and ground, so when activated the coil isn't completely shorted to ground and you're left with a partial signal from that coil in the circuit. The result is less of a drop in output, slight hum cancelling and a change in tone.
You could say the split wire is "tapped" into the wire that joins the coils together, but strictly speaking, I believe that to be incorrect.
I also have a theory (which I've posted about recently) that the 408s both split and tap (splap), one coil tapped in humbucker mode, then untapped (adding 1500 winds) and split in single coil mode. I think there's 5 conductors coming off a 408 and the mini-toggles are DPDT so it kinda backs up my theory.