Middle Primitive Elvish
ramba
root. RAMBA
rambā
noun. wall
rab
root. *wall
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.
In The Etymologies as published by Christopher Tolkien in The Lost Road, this “root” is given as RAMBĀ (Ety/RAMBĀ). However, Carl Hostetter and Patrick Wynne clarified that the root form was actually given as RAB⁽²⁾, and ᴹ✶rambā is simply the primitive form of ᴹQ. ramba/N. rham “wall” (EtyAC/RAMBĀ). The root form ᴹ√RAB² is consistent with other derivatives of the root: ᴹQ. ráva/N. rhaw “bank (especially of a river)”. Tolkien’s continued use of S. ram for “wall” in later writings (S/122; RC/512) indicates the ongoing validity of at least the strengthened form of this root.