出典:Wiktionary
出典:『Wiktionary』 (2026/02/23 18:17 UTC 版)
According to De Vaan, from Proto-Italic *lakus, from Proto-Indo-European *lókus (“lake, pool”); the reason for the change to *a is debated, but perhaps from velarized *[ɫ]. Regarding this proposed phonological development, Schrijver notes that the form lacus may be the only positive evidence for such a sound law, rendering the existence of the rule uncertain. Cognate with Ancient Greek λάκκος (lákkos, “cistern, tank, pit”) and 古期英語 lagu (“sea, ocean, flood”). More at lay.
lacus m (genitive lacūs); fourth declension
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