A fairly common feminine suffix appearing as -il in Sindarin, either formed on its own or as a variant of the feminine suffix -iel. This suffix was also common Noldorin words in The Etymologies of the 1930s, along with an alternate form -ril that seems to be a feminine agental suffix, the equivalent of masculine -(r)on, seen in pairs like N. melethril/melethron “lover” and N. odhril/odhron “parent” (Ety/MEL, ONO). The -il suffix and its -ril variant are seen all the way back in the Gnomish Lexicon of the 1910s in pairs like G. gwadhril/gwadhron “inhabitant” (GL/47) and G. ainil/ainos “god”, female and male respectively (GL/18). So it seems this feminine suffix was well established in Tolkien’s mind.
Sindarin
-th
suffix. abstract noun
-as
suffix. abstract noun
-il
suffix. feminine suffix
-in
suffix. plural suffix
i glinn hen agorer edain mi velerian, ach hí in ellath îr ed epholar
*this song Men made in Beleriand, but now the Elves alone (?remember) it
sen
pronoun. this
thranduil
masculine name. Vigorous Spring
Father of Legolas (LotR/240) translated “vigorous spring”, a combination of tharan “vigorous” and the lenited form of tuil “spring” (PE17/27, 187).
Conceptual Development: In the drafts of the Lord of the Rings appendices, Tolkien indicated that this name was Lemberin (PM/36), so it is possible he considered making this name Nandorin like that of his son Legolas, but elsewhere he and his name were clearly marked as Sindarin (UT/256, PE17/27).
tûr
control
(i dûr, o thûr, construct tur) (mastery, power; master, victor, lord), pl. t**uir (i th**uir), coll. pl. túrath
tûr
master
(i dûr, o thûr, construct tur) (victory, power, control; victor, lord), pl. t**uir (i th**uir), coll. pl. túrath
tûr
master, mastery
(i dûr, o thûr, construct tur) (victory, power, control; victor, lord), pl. t**uir (i th**uir), coll. pl. túrath
tûr
mastery
(i dûr, o thûr, construct tur) (victory, power, control; victor, lord), pl. t**uir (i th**uir), coll. pl. túrath
tûr
power
(i dûr, o thûr, construct tur) (victory, mastery, control; master, victor, lord), pl. t**uir (i th**uir), coll. pl. túrath.
tûr
victor, victory
(i dûr, o thûr, construct tur) (mastery, power, control; master, lord), pl. t**uir (i th**uir), coll. pl. túrath
@@@ mostly seems to use base vowel between suffix and root