Surah Sad 38:31

إِذْ عُرِضَ عَلَيْهِ بِٱلْعَشِىِّ ٱلصَّـٰفِنَـٰتُ ٱلْجِيَادُ

[Mention] when there were exhibited before him in the afternoon the poised [standing] racehorses.

Translation: Saheeh International

Tafsir

When one evening — which is the period after midday — there were displayed before him the prancing steeds al-sāfināt ‘horses’ is the plural of sāfina which denotes a horse standing on three legs with the fourth supported on the edge of the hoof and derives from the verb safana yasfinu sufūnan; …

Excerpt from Tafsir al-Jalalayn, commentary on 38:31, via Quran.com. The reader has the full commentary and 9 more tafsirs.