Was is a past form of the word be.
An example of was is someone saying they were going to the park, but now they're not.
Origin of was
From Middle English was, from Old English wÃ¦s, from Proto-Germanic *was, (compare Scots was, Dutch was, Low German was, German war, Swedish var), from Proto-Indo-European *hâ‚‚wes- (“to reside"). 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 is from Proto-Indo-European *bÊ°ew- (“to become"). The words is and are are both derived from Proto-Indo-European *hâ‚es- (“to be"). Lastly, the past forms starting with w- such as was and were are from Proto-Indo-European *hâ‚‚wes- (“to reside").