Where does “seaweed” come from?

I cannot write this etymology in good faith. The chain provided contains logical problems that make it impossible to construct an accurate sentence: 1. "Sea" and "wee" are listed as separate English etyma for "seaweed," but the chain doesn't show how they combine or relate to each other. 2. The chain jumps from "Old English wēod" (a word meaning "weed/plant") to "Latin sedes" (meaning "seat/dwelling"), which is a semantic and phonetic disconnect that cannot be bridged by the given information. 3. "Latin se" appears to be a fragment without clear connection. 4. Both "sed-" (meaning "sit") and "weǵʰ-" (meaning "move/convey") appear in the PIE roots, but it's unclear which (if either) connects to the Old English term. 5. The known meaning is listed as "(

seaweed (English): Any of numerous marine plants and algae, such as...

Definitions

  1. Any of numerous marine plants and algae, such as...

Ancestry of “seaweed”, step by step

seaweed traces back through two separate lines of ancestry.

via English sea

StepLanguageWordMeaning
1EnglishseaA large body of salt water; A lake, especially if...
2Middle Englishseesea, ocean; A body of water, a lake; seat, chair
3Old Englishsea, lake
4Proto-West Germanicsaiwisea
5Proto-Germanicsaiwizsea, ocean
6Proto-Germanicsīhwanąto filter
7Proto-Indo-Europeanseykʷ-to moisten; to filter
8Proto-Indo-Europeansey-to be wet; dribble; run; to stretch one's arm;...

via English weed

StepLanguageWordMeaning
1EnglishweedAny plant regarded as unwanted at the place...
2Middle Englishweed
3Old Englishwēodweed
4Proto-West Germanic*weudweed (unwanted plant)

Words derived from “seaweed

Every word from Proto-Indo-European sey-Every word from Proto-Indo-European seykʷ-Every word from Proto-Germanic sīhwaną