On the Etymology of zhe sa:
Chung-tshe-ring in an online article in Tibetan (i.e. Zhe sa zhes pa’i tshig don dang khyab khong) records three possible speculative etymologies of the Tibetan word zhe sa. First, zhe sa is derived from rje sa, that is, “object of respect” (rjed par bya’i ba’i yul), where rjed par byed (in Old Tibetan) is said to be synonymous with mchod par byed. Second, zhe sa means “field or one in whom (sa) or the object for which one has respect from the bottom of one’s mind (zhe)” (zhe bsam pa’i gting nas rang gi mos gus yod pa’i sa’am yul). Third, zhe means “field (sa) or object which is worth respecting from [the depth of one’s] yid, sems, or, zhe ‘mind’ (yid can [= dam?] zhe’am sems kyis gus par ’os pa’i sa’am yul). The author then provides his assessment of all three etymologies.
For details, please read: http://www.sherig.org/tb/?page_id=8966.