BOT was the abbreviated version of "BUILD, OPERATE, and TRANSFER," which referred to the transferring method of civilian construction after operation. The government had appointed a civilian company to build and operate construction for a while, but later took back the construction responsibilities and ran it by themselves.
The major focus of BOT were infrastructure constructions. The government did not have enough money to operate, so it transferred its rights to civilian companies. Those companies constructed buildings. The companies had a period of time to run the construction before they had to give it back to the government. Through this method, the companies could make up for the constructions fees, as well as benefit from the builds.