An archaic word for “lion” mentioned in the Outline of Phonology (OP2) from the 1950s, versus more common Q. rauro (PE19/99, 104).
Conceptual Development: This word has a lengthy history in Tolkien’s conception of Elvish, dating all the way back to ᴱQ. rau “lion” in the Qenya Lexicon of the 1910s, a derivative of the early root ᴱ√RAVA (QL/79). In the Declension of Nouns from the early 1930s, Tolkien had rú “lion” (PE21/40). It appeared in The Etymologies from later in the 1930s as ᴹQ. rá “lion” derived from primitive ᴹ✶rāu [rāw] under the root ᴹ√RAW, with plural form rávi (Ety/RAW).
In the Outline of Phonetic Development (OP1) from the 1940s Tolkien had (unglossed) rāva < rāwa (PE19/62), but in Notes for Qenya Declensions from this same period Tolkien had (unglossed) rāu < rắwă (PE21/69). The last clear mention in currently published materials is in the Outline of Phonology (OP2) from the 1950s, as discussed above.
The common Quenya word for “lion” (more literally “roarer”) appearing in the Outline of Phonology (OP2) from the 1950s, as opposed to archaic Q. †rá (PE19/99, 104); see that entry for further discussion of its conceptual development.