Quenya 

er

one, alone

er cardinal "one, alone" (ERE, VT48:6, VT49:54), in an early source also adv. "only, but, still" (LT1:269); Eru er "one God" (VT44:17; er was here emended by Tolkien from erëa, which seems to be an adjectival form *"one, single".)