ὄγκοι (ónkoi, “hooks”),
Although that exists, Epíkouros mostly uses:
"ὄγκος (B), ὁ, bulk, size, mass of a body"
ὁ ὄγκος is really his main word for "particle."
I fully agree with your point, even using this example I could see us being "oncologists" instead of "atomists" (but that word was taken for other uses).