The name of the sword of Fingolfin “that glittered like ice” (S/152). The name is an elaboration of [ᴹQ.] ringe (ringi-) “cold” (SA/ring).
Conceptual Development: The name ᴱQ. Ringil first appeared in the earliest Lost Tales as the name of the tower holding the northmost lamp that lit the world (LT1/69), later as either the lamp itself (Ety/RINGI) or the sea formed after its fall (LR/32). It was first used as the name of Fingolfin’s sword in The Lays of Beleriand (LB/285). The name ᴹQ. Ringil appeared in The Etymologies from the 1930s as a derivative of the root ᴹ√RINGI, at that point still both the lamp and the sword (Ety/RINGI). In Silmarillion revisions from the 1950s-60s, the name of the lamp was changed to Ormal (MR/7), but Ringil remained the name of Fingolfin’s sword.
Ringil noun, name of one of the great Lamps (pillared on ice), apparently contains ringë (RINGI). The name was later abandoned, as Tolkien decided to call the great Lamps Illuin and Ormal.