رضح doesn't appear in Hans Wehr's Modern Standard Arabic dictionary, but Lane's Arabic-English Lexicon has 3 entries for it, distinguished by diacritics. Select one below for the full classical Arabic definition.

• رَضَحَ Form 1

  1 رَضَحَ ذ , aor. رَضَحَ , (L, Msb, K,) inf. n. رَضْحٌ, (S, L, Msb,) He broke, (S, L, Msb, K,) and bruised, brayed, or crushed, (Msb, TA,) pebbles, (S, K,) or date-stones, (S, L, Msb, K,) &c., (Msb,) with a stone [&c.]; …

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• رَضْحٌ

  رَضْحٌ ذ inf. n. of 1. (S, L, Msb.) [Hence,] نَوَى الرَّضْحِ Date-stones that fall out from others [in the operation of breaking or bruising]. (S, K.) And A date-stone that flies from beneath the stone [called مِرْضَاح].…

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• رُضْحٌ

  رُضْحٌ ذ is a subst. from رَضَحَ; and [as such, as is implied, or rather indicated, in the S,] signifies Broken [or bruised, brayed, or crushed,] datestones; i. q. نَوًى ; (S, K;) as also [i. e. نَوًى رَضِيحٌ]. (K.) [See…

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