On the Origin of the Tibetan Word “sam ṭa”

For quite sometime, I have been puzzled by a Tibetan word that is spelled either sam ṭa or sam ta. The Bod rgya tshig mdzod chen mo (s.v. sam ta), explains it thus: “a wooden tablet with [some] varnish [which serves as a] support/receptacle for [mainly practicing] writing” (yi ge ’bri gzhi’i shing byang rtsi ldan zhig). The word is recorded also in Jäschke 1881 (s.v. sam ta) and one of the meanings given there is indeed “tablets.” Other orthographies have been recorded as well: brtsam grwa, bsam kra, and sab dra. But these seem to merely reflect failed attempts of trying to make sense of the etymology. For a more recent and nuanced explaination of the word, see Kapstein & Clemente 2024: 238, which reads: “An erasable writing board, used for practicing, drafts, and correspondence.” For a beautiful image of a sam ṭa (spelled there samtra), see Dotson & Helman-Ważny 2024: 77 (Fig. 2.24). The meaning of the word as used in the Tibetan traditions seems to be clear. What is puzzling is the origin of the word. We may all agree that the word has an Indic tinge. If this obviously Tibetanized word has an Indic or Sanskrit origin, what could it be?

My hypothesis is that the Tibetanized word sam ṭa is derived from (or, is a contracted form of) sampuṭa. That some Tibetan scholars contracted the component sampuṭa (in the Sampuṭatantra) as sam ṭa is confirmed. Now, the question is why Tibetans called an erasable wooden writing board a sampuṭa and if this would somehow make sense also from an Indic perspective. In Sanskrit, sampuṭa is said to have a meaning of a “case or box or casket (for jewellery)” (MW, s.v. sampuṭa). If we examine the image of a Tibetan sam ṭa, we will realize that it is a kind of a case, box, or, casket though admittedly rectangular and not spherical in shape. What is, however, even more interesting is that in Sanskrit there is said to be the construction sampuṭe √likh (with genitive), which means, “to write down to the credit of”). The attestation for this Sanskrit expression, Professor Isaacson tells me, is, however, rare. The only source for it is the Kathāsaritsāgara given in PW (and MW). Such a usage seems to connect sampuṭa with the act of writing down something. Thus, for now, I propose that the Tibetan word sam ṭa has been derived from Sanskrit sampuṭa.