Old Korean orthography generally transcribes only the final syllable or coda consonant of a native noun, here written with 音 (*-m). The first character refers to the semantic value of the word instead. Thus the Old Korean word for "palm of the hand", in Chinese 掌 (zhǎng), ended with *-m. However, the Middle (and Modern) Korean word for "palm" is the compound 소ᇇ바닥 (swon-s-patak), literally "hand-floor", which does not involve -m. Presumably, the original Old Korean form went extinct and was displaced by the periphrastic Middle Korean construction.
Due to the opaque orthography, Old Korean is conventionally transliterated and romanized by casting back the Middle Korean reflexes. In the case of this word, the typical transliteration is either *SWON-S-POLOm, after Middle Korean 손 (swon, “hand”) and ᄇᆞᄅᆞᆷ (polom, “wall”), or *SWON-S-PATAm. The former is because of the existence of the Modern Korean word 손뼉 (sonppyeok, “palm-side of the hand”), literally "hand's wall". However, the Modern Korean compound is based on the Sino-Korean word 벽 (byeok, “wall”), and *소ᇇᄇᆞᄅᆞᆷ (*swon-s-polom) is not actually attested in Middle Korean. The latter is simply a version of the Middle Korean form with the coda changed to meet the Old Korean phonogram. Both forms should be considered as the result of the need to transcribe Old Korean into some phonetic form in academic reconstructions, rather than even an approximately accurate reading.
掌音 (-m)