Greatest of the dragons, slain by Eärendil (S/252). His name is translated “Biting-Storm”, possibly a combination of anc “jaw” and a variant of [N.] alagos “storm of wind”.
Conceptual Development: This name first appeared in Silmarillion drafts from the 1930s (SM/160). The name is translated in The Etymologies from the 1930s (Ety/NAK) but not in later writings. The decomposition above is derived from the entries in The Etymologies (Ety/ÁLAK, ÁNAK, NAK).
anc (“jaw, row of teeth”) + alag (“rushing, impetuous”) + #on (#male ending); LRW:417 translates it as “Biting Storm”, the final element probably alagos “storm”, with a change of the last consonant.