Analysis of information sources in references of the Wikipedia article "Luis (letter)" in English language version.
The kennings point to an association of this letter name with either luise/loise 'flame, blaze' or lus 'plant, herb'. The word itself is not reliably attested in a context which would indicate its precise primary meaning but it is clearly related either to the root *leuk- 'to shine' or *leudh- 'to grow', either confirming /l/ as the value.
