Jakrawan
(P., Skt.)
The ancient Theravada tradition saw a flat world with Heaven above and Hell below, which changed at a later stage in a
ten-thousand world vision. According to the Traiphum, the universe has been for ever occupied by an infinite number of
Chakrawans (groups of worlds) all exactly similar, and each embracing a world of men, with a series of heavens and hells. Each
of these worlds (solar systems) depends on a central mountain named Phra Meru. Around Mount Meru are eight circular belts of
ocean, divided from each other by seven annular mountains (Satta Boriphan). Outside of all is an eighth rim of mountains, called
the "Crystal Walls of the World" or "Mount Chakrawan", the crystal annular mountain which encircles the system. [1]

[Ref: The Wheel of The Law - Alabaster Henry (1871) - page 10/257.]
Jaranam
Jaranam is a niche inside a prang or chedi.
Jataka
(P., Skt.)
[Chadok (Th,)] Birth Stories, the stories of the Buddha's previous lives.

[Ref: An outline of the History of Religious Architecture in Thailand - Sonthiwan Intralib (1991).]
Junkceylon
Ancient name for Phuket.
   
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Siampedia by Tricky Vandenberg