Phone jack schematic and datasheet meaning
"Tip spring" would be the inverted "V" on the schematic, and "shunt terminal is the downwards-pointing arrow.  "Terminal" would be the body of the mating plug, and "Tip spring" would contact the tip of the plug.

"Shunt terminal" is a switch contact that is normally connected to the Tip Spring, and is disconnected when the plug is inserted in the jack.