A word for the seeing stones of Númenor, a combination of palan “far” and some form of the root TIR “see” (Let/427), hence: “far-seer” or “far-gazer” (LotR Index; PE17/25, 86). This word is unusual in that it has a long vowel in its final syllable, something that does not normally occur in Quenya words. The ancient form of this word was palantīrā̆ (Let/427), and the reduction of short vowels in long compounds was not unusual in Quenya, for example: Valinor as a shorter form of Valinórë. However, after such reductions long vowels in final syllables tended to shorten, so the expect form would be palantir, not palantír. In one place Tolkien described this word as a “a Numenorean formation” (PE17/86), perhaps as a way of explaining the unusual retention of a long vowel in its final syllable.
Because of this long vowel, the proper pronunciation of this word is in dispute. The usual rules for Quenya stress would put the stress on the second syllable: paLANtír. The speech coaches for Peter Jackson’s Lord of the Rings movies instructed the actors to pronounce this word like English “lantern” to help them remember this stress pattern. However in private notes Tolkien wrote pálan-tìr (PE17/86), indicating primary stress on the first syllable and secondary stress on the last: PAlanTÍR. Perhaps the long vowel in the final syllable is retained to enforce this stress. Compare also María with an abnormal long vowel before another vowel, also enforcing a stress pattern that would be atypical for Quenya if all the vowels were short.
Conceptual Development: This word appeared in the Etymologies of the 1930s where it was probably a later addition. In its earliest appearances, both in Etymologies and the drafts of The Lord of the Rings, it was Palantir with a short i (Ety/PAL, TIR; WR/76).
tir- vb. "watch, watch over, guard, heed", 1st pers. aorist tirin "I watch", pa.t. tirnë (TIR), imperative tira (VT47:31) or á tirë (PE17:94), future tense tiruva "shall heed" in Markirya (also MC:213, 214); also in CO with pronominal endings: tiruvantes "they will guard it" (tir-uva-nte-s "guard-will-they-it"). The stem also occurs in palantíri (q.v.), Tirion place-name "Great Watchtower", a city of the Elves (SA:tir; in MR:176 the translation is "Watchful City")