APB (Advanced Peripheral Bus) IP is a reusable intellectual property (IP) block that implements the APB protocol for efficient communication with low power peripherals. It simplifies the integration of devices like UARTs, timers, and GPIOs in SoCs by providing a simple, low latency interface. APB IP ensures compliance with AMBA standards and supports easy interfacing with higher-performance buses like AHB or AXI through bridges.