This I interpret from Chris Tedders message at Aker-Akeru thread:
[www.hallofmaat.com]

Aker (Akr) and Akhet (Axt) sometimes share the same 'strip of land' [DDeden: same rootword] det., N18, but otherwise they are written differently - the A in Akr is the 'Egyptian vulture', G1 [DDeden: vulture = open field], but the Ax in Axt, is the 'crested ibis' biliteral sign, G25 [DDeden: ibis = stone pick/chisel/compass (beak)]

'Akhet' (Axtj), (Khufu's pyramid name, designated whole site at Giza in MK) actually referred to Ax-cut-Gem=Ak-khet-Giza, where the whole pyramid gem(s) was an amalgamation of axed "chips" (blocks).

So now we have three similar words relating to cutting action:
[Aker=earth-axe (plow)~"acre", Aker as symbol of cut (plowed-harvested) field?] (field, strip, agri-)
[Akeru=water-axe (boat)~"aqua", Akeru as symbol of cut (navigated) waters?] (dugout, boat, aqua-)
[Akhet=stone-axe (chisel)~"akhet/pet", Akhet as symbol of cut (sculptured) stone?] (petro, cut, petra-)

(Note: "stone-axe" above refers to a tool cutting the stone. So the cutting tool might be a copper saw/iron chisel/quartz ball/flint flake. What paleoanthropologists refer to as the paleolithic Acheuleun "Hand-Axe" or Biface was NOT primarily an axe. It was a bait-trap inserted into a fish or chunk of meat used to disable/kill predator/pest competitors at waterside, and modeled after bilateral clamshells, which were used at shorelines for the same purpose (resembling clams with cutting edge all around), to make the area safe and allow easier hunting/gathering. So when I refer to an "axe/aht/ak" I mean the hammerstone, or chisel or axe. However people of different languages used the Ax- word in different ways, and altered the pronunciation and spelling. The words "action, reaction" derived from the motions of splitting or swinging in stonework.