Where does “assoreamento” come from?

assoreamento (Portuguese) comes from Portuguese sob, from Old Portuguese sob, from Latin sub, from Proto-Italic supo, from Proto-Indo-European upó, from Proto-Indo-European h₃ewp-.

assoreamento (Portuguese): siltation/silting accumulation of debris (sand, pebbles, silt, etc.) in areas of low elevation of the riverbed, especially in the final part

Definitions

siltation/silting accumulation of debris (sand, pebbles, silt, etc.) in areas of low elevation of the riverbed, especially in the final part

Ancestry of “assoreamento”, step by step

assoreamento traces back through two separate lines of ancestry.

via Portuguese sob

Step	Language	Word	Meaning
1	Portuguese	sob	under
2	Old Portuguese	sob	—
3	Latin	sub	under, beneath; behind; at the feet of
4	Proto-Italic	supo	under
5	Proto-Indo-European	upó	under, below
6	Proto-Indo-European	h₃ewp-	—

via Portuguese areia

Step	Language	Word	Meaning
1	Portuguese	areia	sand
2	Old Portuguese	arẽa	sand
3	Latin	arēna	—
4	Latin	harēna	sand
5	Latin	hasena	—

Every word from Proto-Indo-European h₃ewp- →Every word from Proto-Indo-European upó →Every word from Proto-Italic supo →