هيأ doesn't appear in Hans Wehr's Modern Standard Arabic dictionary, but Lane's Arabic-English Lexicon has 2 entries for it, distinguished by diacritics. Select one below for the full classical Arabic definition.

• هَآءَ Form 1

  1 هَآءَ ذ , aor. يَهَآءُ and يَهِيْءُ, (K; the latter not of respectable authority, Lh;) inf. n. هَيْئَةٌ, He was, or became, of good, or goodly, form or appearance, or other properties denoted by the term هَيْئَة, q. …

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• هيّأ Form 2

  2 هيّأ ذ , inf. n. تَهْيِئَةٌ and تَهْيِىْءٌ, [primarily signifies He invested him with, or made him to have, هَيْءَة, as meaning garb, guise, &c. See Bd xviii. 9. -b2- And hence,] He prepared, provided, disposed, arrang…

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