Where does “sąsiada” come from?

sąsiada (Polish) comes from Polish -a, from Old Polish -ą, from Proto-Slavic -a, from Proto-Indo-European -ōd.

Ancestry of “sąsiada”, step by step

StepLanguageWordMeaning
1Polish-aforms nominative feminine nouns
2Old Polish-ąforms third person plural of verbs
3Proto-Slavic-aid
4Proto-Indo-European-ōd—
Every word from Proto-Indo-European -ōd →Every word from Polish -a →Every word from Proto-Slavic -a →