The story
- Proto-Indo-European*h₂wes-
- Proto-Germanic*was
- Old Englishwæs
- Middle Englishwas
- English todaywas
From Middle English was, from Old English wæs, from Proto-Germanic *was, from Proto-Indo-European *h₂we-h₂wós-e from *h₂wes- (“to reside”), whence also vestal. See also Scots was, West Frisian was (dated, wie is generally preferred today), Dutch was, Low German was, German war, Swedish var); also Kamkata-viri vos-, Sanskrit उवास (uvā́sa). The paradigm of “to be” has been since the time of Proto-Germanic a synthesis of three originally distinct verb stems. The infinitive form be and its derived forms been and being are from Proto-Indo-European *bʰuH- (“to become”). The present-tense indicative forms am, is, and are are both derived from Proto-Indo-European *h₁es- (“to be”). Lastly, the past forms starting with w- such as was and were are from Proto-Indo-European *h₂wes- (“to reside”).
Words from the same roots
Proto-Indo-European*bʰuH- all →
Proto-Indo-European*h₁es- all →
Etymology from Wiktionary, CC BY-SA 4.0.