The Quenya name of Turgon from which his Sindarin name is derived, a compound of turu- “master, have victory over” and cáno “commander” (PM/345), glossed in one place as “Ruling Lord” (PE17/113).
Conceptual Development: The Qenya name for Turgon appeared in the earliest Lost Tales as ᴱQ. Turondo (LT1/115). According to Christopher Tolkien, the initial element of the name at this stage was probably from ᴱ√TURU “be strong”, but the meaning of the second element was unclear (LT1A/Turgon). It might have been ᴱQ. ondo as indicated by its later translation “Lord of Stone” (see below). In these and later stories, the character was usually referred to by the name Turgon, and the Quenya name vanished for many decades.
In the 1950s, J.R.R. Tolkien revisited the question of Turgon’s Quenya name after he decided that Quenya was the native language of the Noldor (PE17/112-3). He first considered and rejected the earlier name Q. Turondo, now glossed “Lord of Stone”. He replaced this with Turucāno “Ruling Lord”, changing that in turn to Q. Turukondo “Victory Prince”. At this stage, this name was his “title”, while his given name was Sarafinwë.
In a later essay from 1968 (PM/345), Turukáno reappeared as the Quenya name of Turgon, now also his given name, effectively replacing both Turukondo and Sarafinwë.
Turucáno ("k") masc. name "Turgon" (PM:344). The meaning is something like "powerful commander" (see cáno). Another version gives Turondo "lord of stone" as the Q name of Turgon(d). (PE17:115), with a wholly distinct final element.