Resistors are said to be connected together in "Parallel" when both of their terminals are respectively connected to each terminal of the other resistor or resistors. The voltage drop across all of the resistors in parallel is the same. Then, Resistors in Parallel have a Common Voltage across them and in our example below the voltage across the resistors is given as:

VR1 = VR2 = VR3 = VAB = 12V

In the following circuit the resistors R1R2 and R3 are all connected together in parallel between the two points A and B.

Resistors in Parallel

Definition and diagram provided by Electronic Tutorials

  Because the voltage across all three resistors, but each resistor only handles a fraction of the current (The current release from the power source is equal current returned to the power source, so when the circuit slips into multiple pathways, the current is divided between each pathway).  The equivalent resistance is less then the sum of the total resistance.