zeroth

/ˈzɪroʊθ/
adjective
  1. Coming before what is usually considered the first; having a position of zero in a numbered series.
    • In computer science, the zeroth element of an array is often the first item.
    • The zeroth step in the recipe is to preheat the oven.
    • The zeroth chapter of the book introduces the main ideas before the first chapter.
Synonyms
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