A travel documentary features Tongdosa temple (통도사) near Ulsan. According to Wikipedia, the name means Salvation of the World through Mastery of Truth. –sa means temple, so I can only assume that tong means ‘salvation of the world’ and do means ‘mastery of truth’, which is a lot of meaning in one syllable each.
The first problem is that Wikipedia, as an open-source encyclopedia, is only as authoritative as the sources its editors cite. The citation for this particular piece of information is a perfectly ordinary travel guide. The temple’s own site doesn’t mention the meaning of the name (at least the English version and Google’s translation of the history of the temple in Korean don’t), and the only other similar reference I can find (a perfectly ordinary travel website) says “The name ‘Tongdosa’ was named after the belief that mankind can be saved through Buddhism”.
Assuming that that meaning is, in fact, true, the second problem is that no online or paper dictionary I have consulted has entries anything like this. But, just as Koreans turn 디지털 카메라 (digital camera) into 디카 (di-ka), it is possible that the name is a shortening of longer words tong(something) do(something), the equivalent of sal(vation) and mast(ery) making salmast temple. In fact, compare 통일 (tong-il, unification) and the 통일교 (Unification movement, Unification church, ‘the Moonies’).
As a general rule, throughout all languages, simple syllables and words have simple meanings, and complex meanings are represented by complex words. Unless I actually go there and ask someone, I will probably never know what the name actually means.
[PS Wikipedia also records the Chinese character name 通度寺. Google Translate translates 通 as, probably most relevantly, through, and 度 as degree, extent, measure, so the name is probably Sino-Korean rather than Korean.]