quantum circuit
The program a quantum computer runs: a sequence of operations on its qubits.
A quantum circuit lists, step by step, the operations applied to each qubit. These operations are called gates. Some act on one qubit, others link two qubits together. At the end, the qubits are measured. A longer circuit can do more, but each extra step adds another chance for an error.
Think of it as
Like a recipe card: a fixed list of steps, in order, ending with the dish being tasted.
Example
A research team writes a circuit of 500 gates on 16 qubits to model a molecule. They send it to a cloud quantum computer, which runs it and returns the measured results.