endë noun "core, centre, middle" (NÉD, EN, VT48:25)
Quenya
endë
noun. centre, middle, centre, middle; [ᴹQ.] core
endë
core, centre, middle
enquë
cardinal. six
The Quenya word for “six” derived from the root √ENEK of the same meaning (PE17/95; VT48/7-10; Ety/ÉNEK). The modification of ancient ✱enek- to ✱enekwē was a Quenya-only innovation, influenced by minquë “eleven” and yunquë “twelve” (VT48/7).
Conceptual Development: The word ᴱQ. enqe “six” dates all the way back to the Early Qenya Grammar (EQG) of the 1920s, but there it had a variant enekse (PE14/49, 82). The Qenya Lexicon of the 1910s had ᴱQ. ende “six” under the early root ᴱ√ENE of the same meaning (QL/35).
enquë
cardinal. six
enquë ("q") cardinal "six" (ÉNEK, VT48:4, 6, 9, VT49:57); enquëa ordinal "sixth" (VT42:25); see also enquië. According to VT48:8, the word for "six" may have been encë ("k") in very early Quenya (the form is asterisked by Tolkien), but this was altered to enquë under the influence of yunquë "twelve" (perceived as meaning "2 times 6", *yú-enquë, with the prefix yú- "twi-").
The word ᴹQ. ende first appeared in The Etymologies of the 1930s, glossed either “middle, centre” (Ety/ÉNED) or “core, centre” (Ety/NÉD), and derived from the root ᴹ√ENED “middle” (Ety/ÉNED). In notes from late 1960s Tolkien had {ened >>} ente “centre”, which he clarified was “not used of emotions or thought only physical” (VT41/12). In this context it was derived from √HENET “middle” (VT41/16). But in other writings from the late 1960s, the word as again ende from √ENED “middle” (VT48/25), and I believe √HENET > ente was a transient idea.
Neo-Quenya: Base on its 1930s glosses and the meaning of 1960s ente, I believe ende is a noun referring to a physical centre.