Circuit/ˈsɜːrkɪt/ Definition 1 of 5Pro Tip 1/3Technical Use Mainly used in technical or scientific discussions. Ensure that the integrated circuit in the device is handled properly. Pro Tip 2/3Not Always Visible 'Circuit' might refer to complex, hidden paths inside devices. The smartphone's performance relies on its micro-circuits. Pro Tip 3/3Common Pairings Often appears with 'breaker' to mean a safety device in power systems. When the power surge happened, the circuit breaker tripped.