A word for the palm or the flat of the hand in notes from 1968, derived from primitive ✶palátā based on the root √PAL “wide, extended” (VT47/8-9). More specifically, it described “the hand held upwards or forwards, flat and tensed (with fingers and thumb closed or spread)”. Tolkien went on to describe various Elvish hand gestures using a flat hand (VT47/8, 13): a single upward palm to ask for gift, a pair of upward palms to offer service, a palm held forward to forbid an action or refuse a plea. Greetings were made with palms outward and arms held wide (indicating no held weapons), or single palm held up but backwards (so not in refusal), or more casually held sideways.
Conceptual Development: This word has a clear precursor: ᴱQ. paltya “flat of hand” from the early root ᴱ√PḶTYḶ in the Qenya Lexicon of the 1910s (QL/74). Despite the 50 year gap, the forms and meanings of these two words were too close to be a coincidence. ᴱQ. paltya also appeared in the Poetic and Mythological Words of Eldarissa of the 1910s with the slightly different gloss “palm of hand” (PME/74). As for ᴱQ. palta (from ᴱ√PALA “flatness”), this meant “shelf” rather than “palm” in the Qenya Lexicon (QL/71).
Neo-Quenya: For purpose of Neo-Quenya, I think palta can mean both “palm” and “shelf”.
palta (1) noun "the flat of the hand, the hand held upwards or forwards, flat and tensed" (with fingers and thumb closed or spread) (VT47:8, 9)