What is the designated airport code for O'Hare International Airport?

O'Hare International Airport, one of the busiest airports in the world and a major hub for domestic and international flights, is designated by the airport code ORD. This code is derived from the airport's original name, Orchard Field, where it was initially built during World War II. The use of "ORD" has become standard in the aviation industry, and it is recognized internationally. The other options do not correspond to O'Hare's official designation—terms like OHA, OHQ, and OHI do not relate to any major airport or commercial flight operations in the same way that ORD does. Understanding the significance of airport codes is essential for navigation and communication in air travel.