Where does “onesidedness” come from?

onesidedness (English) comes from English onesided, from English one, from Middle English one, from Middle English onen, from Middle English -en, from Old English -en, from Old Norse -inn, from Proto-Norse -īna- — adjectival suffix.

Ancestry of “onesidedness”, step by step

StepLanguageWordMeaning
1EnglishonesidedBiased, only showing one side or point of view on...
2EnglishoneThe number represented by the Arabic numeral 1;...
3Middle EnglishoneAlternative form of on; Alternative form of hone;...
4Middle Englishonento unify; to join together; to gather together;...
5Middle English-enDenotes the past participle form when attached to...
6Old English-enmæġþ + API → mæġden; cocc + API → cycen, cicen;...
7Old Norse-innUsed to create adjectives from nouns, meaning...
8Proto-Norse-īna-
9Proto-Germanic-īnaz-en
10Proto-Indo-European-iHnosCreates adjectives of materials
11Proto-Indo-European-no-adjectival suffix
Every word from Proto-Indo-European -no-