Koh translates as Island...
Koh means Island and Khao means mountain although they sound (to western ears) the same. These are translations and the sound cannot fully be conveyed in the English language. Other spellings for Koh or Island are: Ko, Kao and Kho. Such travel guides like the Lonely Planet and the online wiki's use the Ko spelling, on the Island itself the word is mostly spelt, Koh.
There are a series of small Island around koh Phangan often not more than a few hundred meters from the shoreline. They are in no particular order: Koh Tae Nok, Koh Tae Nai, Koh Ma, Koh Tung Ku, koh Tung Ka, Koh Wao and Koh Hin Bai. Koh Tae Nok is a small island off limits to holiday makers and travellers as it is privately owned. Like Koh Tae Nai, Koh Tae Nok is located offshore from Thong Sala, the main entry port to Koh Phangan.
Phangan' national forest reservation consists of the following reserves: Namtok Than Sadet forest, Khao Lat Kaeo forest, Khao Khai forest, Khao Ta Luang forest, Khao Hin Nok forest, Laem Pho-Laem Kata Khwa forest and Khao Fai Mai forest.