A name appearing only in The Etymologies from the 1930s (Ety/LAS²). Its initial element is derived from the root ᴹ√LAS² “listen”, probably *✶lastā given is Quenya cognate Lastalaika, where the [st] became [s] before a consonant and then the medial [s] became [θ] before [l], as in othlon. Its final element is a suffixal form of lhaeg “sharp”.

Conceptual Development: This name appears to be a variation on earlier G. Legolast “Keen-sight”.