Early Quenya
mitta
noun. piece, bit (of indeterminate size)
mitta
preposition/adverb. in, into, inwards
mitta-
verb. to enter (intr.)
i mitta ’n·felda aksínen
the worst piece of steel
int
adverb. inwards
There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.
Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.
The Qenya Lexicon of the 1910s had ᴱQ. min (mind-) “a bit, piece” under the early root ᴱ√MINI (QL/61). The English-Qenya Dictionary of the 1920s instead had ᴱQ. mie “bit” = “small piece” (PE15/70) while Early Qenya word-lists of this same period had mie “a bit” (PE16/143). The Qenya word mie was also mentioned in contemporaneous Early Noldorin word-lists as a cognate to ᴱN. mui “crumb”, both derived from ᴱ✶smeigé (PE13/150).
The English-Qenya Dictionary of the 1920s had a variant form ᴱQ. mitta “bit = of indeterminate size” (PE15/70). The contemporaneous Early Qenya Grammar used mitta with the meaning “piece” (PE14/48, 81). These 1920s words seem to be based on a root ✱ᴱ√MIKI; compare adverbial ᴱQ. mike “a (little) bit” (PE14/48, 80-81; PE15/70).
Neo-Quenya: For purposes of Neo-Quenya, I would update these words to ᴺQ. nihta “piece, bit, small part” derived from the later root √NIK.