The name Bangkok is actually a Western nickname.
The original village that was called Bangkok centuries ago no longer exists. Modern Bangkok's proper Thai name is Krung thep mahanakhon amorn ratanakosin mahintharayutthaya mahadilok popnoparat ratchathani burirom udomratchanivetmahasathan amornpiman avatarnsathit sakkathattiyavisnukarmprasit, which, according to the Guinness Book of Records, is the longest location name in the world. In English, this translates into "The city of angels, the great city, the residence of the Emerald Buddha, the impregnable city of Ayutthaya of God Indra, the grand capital of the world endowed with nine precious gems, the happy city, abounding in an enormous Royal Palace that resembles the heavenly abode where reigns the reincarnated god, a city given by Indra and built by Vishnukarn."
Thais simply refer to their capital city as Krung Thep, or the "City of Angels."