Wa (Thai: วา[wāː], also waa or wah, abbreviated ว.) is a unit of length, equal to two metres (2 m) or four sok (ศอก.) Wa as a verb means to outstretch (one's) arms to both sides, which relates to the fathom's distance between the fingertips of a man's outstretched arms. The 1833 Siamese-American Treaty of Amity and Commerce, reads, "[The] Siamese fathom...being computed to contain 78 English or American inches, corresponding to 96 Siamese inches."[1] The length then would have been equivalent to a modern 1.981 metres.[2] Since conversion to the metric system in 1923,[3][4] the length as derived from the metre is precisely two metres, but the unit is neither part of nor recognized by the modern International metric system (SI).
^"History of weights and measures in Thailand.htm". Northern Weights and Measures Center (Thailand). April 2004. Retrieved September 26, 2011. ..."Weights and Measures Act, B.E. 2466" [1923 CE]....[superseded by ] "Weights and Measures Act, B.E. 2542"...Government Gazette, Royal Decree Version, Volume 116, Part 29 a, dated 21 April 1999...effective since 18 October 1999
^ประวัติชั่งตวงวัดไทย (in Thai). Northern Weights and Measures Center (Thailand). April 2004. Retrieved September 26, 2011.