√AM² root. “go up”
For all of Tolkien’s life, the Primitive Elvish root for “up” was √AM. Its best known derivatives are probably Q. ambo, S. amon “hill”. Tolkien introduced this root all the way back in the Qenya Lexicon of the 1910s, where Tolkien gave it as ᴱ√AM(U) “up(ward)” (QL/30). In The Etymologies of the 1930s it was ᴹ√AM² “up” (Ety/AM²), and in 1967 notes Tolkien gave it as “AM, go up, especially of climbing” (PE17/157). In a separate set of 1967 notes on comparison, Tolkien said:
But there existed a “base” that was intrinsically “comparative”, √AMA. This signified addition, increase, plus (PE17/91).
Tolkien did not explicitly connect this to √AM “up”, but it seems likely the two were related. See the discussion of √AMA for further details.
References ✧ PE17/146, 157
ᴹ√AM² root. “up”
References ✧ Ety/AM², NDŪ, PEN, UNU
ᴱ√AM(U) root. “up(wards)”
References ✧ LT2A/Amon Gwareth; PE13/109; QL/30