Middle Primitive Elvish
gar
root. keep, hold, possess; maintain, defend
garat
root. *defend
oth
root. fort
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.
A root in The Etymologies of the 1930s, apparently a variant of ᴹ√ƷAR, and having extensions ᴹ√GARAD and ᴹ√GARAT (Ety/ƷAR). It was given various glosses in separate entries such as “hold, possess” and “keep, maintain, defend”, but these glossed entries were all deleted (Ety/GAR; EtyAC/GAR). Two notable derivatives of ᴹ√ƷAR/GAR were ᴹQ. arda “realm, region” and N. ardh “realm” (Ety/ƷAR), apparently transferred to here from the earlier root ᴱ√ƷARA “spread” (QL/32). Both these words reappeared in the Quendi and Eldar essay from 1959-60 as Q. arda and S. gardh “region” from primitive ✶gardā (WJ/402), hinting at the continued validity of the root √GAR, though its later meaning is unclear.