Early Primitive Elvish
gwā
root. *wind
ŋgwa-alassa
noun. ŋgwa-alassa
ŋu̯a
prefix. together, in one
sō
root. *together
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 Qenya Lexicon of the 1910s that Tolkien said was used only for the prefix ᴱQ. so- “grouped, together”, but immediately under it he wrote another (non-prefixal?) root ᴱ√SŌ with a single derivative ᴱQ. sóma “state, condition” (QL/85). There are no signs of either of these functions for this root in Tolkien’s later writing.