: a tutelary god or spirit associated with Vesta and the Penates as a guardian of the household by the ancient Romans
borrowed from Latin Lar-, Lār "tutelary god, tutelary god of the hearth," of uncertain origin
The etymology of the word is perforce linked to speculation on the origin of the Lares, in particularly if they were at first spirits of the dead charged with protecting the household, which would favor a connection with lārva "evil spirit, demon" (applied also to a frightening mask and a puppet in the form of a skeleton; compare larva). The earliest attested form, lases in the Carmen arvalis, would seem to show that the r is the outcome of rhotacism. Assuming that the etymon is of Indo-European descent, D. Kilday ("Latin sāl, pār, mās, and lār," available on academia.edu) proposes that Lar-, Lār results from a paradigm *leh2s, *lh2es, *lh2s (with r of the oblique forms generalized to the nominative), a derivative meaning "desired one," from the verbal base *las- "be unrestrained, avid," seen in Greek lilaíomai "to desire eagerly" and Latin lascīvus "playful, unruly, free from restraint in sexual matters" (see lascivious). Correspondingly, lārva would go back to *lāswā, a substantivized passive adjective in *u̯ó- meaning "woman fit to be desired." A difficulty of this hypothesis is that it would require nearly complete submersion of the words' original meaning. Older literature (as Ernout and Meillet, Dictionnaire étymologique de la langue latine) regards Lār, along with the supposed derivatives Lārentia, the reputed foster-mother of Romulus and Remus, and Lārunda, a goddess of ancient Italy, as most likely of Etruscan origin.