Where does “sea-sickness” come from?

sea-sickness (English) comes from English sickness, from Old English sēocnes, from Old English -nes, from Proto-West Germanic -nassī, from Proto-Germanic -inassuz, from Proto-West Germanic -ī, from Proto-Germanic -į̄, from Proto-Indo-European -íh₂ — Creates collective nouns, which refer to groups...

Ancestry of “sea-sickness”, step by step

sea-sickness traces back through 3 separate lines of ancestry.

via English sickness

StepLanguageWordMeaning
1EnglishsicknessThe quality or state of being sick or diseased;...
2Old Englishsēocnessickness, disease
3Old English-nesUsed to form abstract nouns, usually from...
4Proto-West Germanic-nassīUsed to form abstract nouns, usually from...
5Proto-Germanic-inassuz-ness
6Proto-West Germanic-ness, -th
7Proto-Germanic-į̄-th
8Proto-Indo-European-íh₂
9Proto-Indo-European-h₂Creates collective nouns, which refer to groups...

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 seasick

StepLanguageWordMeaning
1EnglishseasickSuffering from sickness, nausea or dizziness due...
2Middle Englishsee seke
Every word from Proto-Indo-European -h₂
sea-sickness — Etymology, Origin & Word History | Etymology Explorer