The Pauli-X gate, also known as the NOT gate, is a fundamental operation in quantum computing. It acts on a single qubit, flipping its state from |0⟩ to |1⟩ and vice versa. This means that if the qubit is in the state |0⟩, applying the Pauli-X gate will change it to |1⟩, and if it is in the state |1⟩, it will change it to |0⟩. The Pauli-X gate is one of the three Pauli gates, which also include the Pauli-Y and Pauli-Z gates. These gates are essential for manipulating qubits in quantum algorithms. The Pauli-X gate is represented by a specific matrix, and its operation is crucial for creating superpositions and entanglements in quantum systems.