p40

P40 or P-40 is a designation used in different contexts to label unrelated items. The most widely known use is in military aviation, where the Curtiss P-40 Warhawk was a United States fighter aircraft deployed during World War II. Introduced in the late 1930s and produced through the mid-1940s, the P-40 served with the US Army Air Forces and with Allied air forces, including the famous Flying Tigers in China. It saw action in several theaters, notably North Africa and the Pacific, and was valued for ruggedness and ease of maintenance, while being outclassed at high altitude by some newer fighters. Variants included several subtypes with differing armament and equipment.

In biology and biochemistry, p40 is a conventional label used for a protein of approximately 40 kilodaltons in apparent molecular mass. The name is not unique to a single molecule; multiple proteins and subunits across species carry the p40 designation, often as part of larger protein complexes. A common example is p40phox, a regulatory subunit of the NADPH oxidase complex in phagocytes.

In consumer electronics, P40 designates a smartphone model, most prominently the Huawei P40 family released in 2020. The series includes several variants such as the P40 and P40 Pro, which feature high-end cameras and 5G capabilities in some markets. Due to export controls and licensing issues, devices distributed in certain regions did not include Google Mobile Services at launch.