Is there a rule whether a compound word is hyphenated (at a line break) between its components?
potash
is hyphenated as pot-ash
, but potassium
is hyphenated as po-tas-si-um
.
From Merriam Webster:
Origin of POTASSIUM
New Latin, from potassa potash, from English potash
Why is potassium not hyphenated pot-as-si-um
, which would preserve the sense?
Is there some general rule about this?