(ض) وَسَطَ يَسِطُ وَسْطًاwasaṭa yasiṭu wa-sṭan (original form: وَسَطَ يَوْسِطُwasaṭa yawsiṭu): to be in the middle of something, to get into the midst. Only once in the Quran: ﴿فَوَسَطْنَ بِهِۦ جَمْعًا﴾ (Al-ʿĀdiyāt 100:5)
وَسَطٌwasaṭ (with two fatḥahs, noun (ism dhāt)/adjective): middle; hence the sense of "moderate and best", since excess and deficiency lie at the two extremes and good lies in the middle. ﴿وَكَذٰلِكَ جَعَلْنٰكُمْ اُمَّةً وَّسَطًا﴾ (Al-Baqarah 2:143)
اَوْسَطُawsaṭu (elative, ism tafḍīl): middle; best, most moderate. ﴿مِنْ اَوْسَطِ مَا تُطْعِمُوْنَ اَهْلِيْكُمْ﴾ (Al-Māʾidah 5:89); ﴿قَالَ اَوْسَطُهُمْ اَلَمْ اَقُلْ لَّكُمْ لَوْلَا تُسَبِّحُوْنَ﴾ (Al-Qalam 68:28)
وُسْطٰىwusṭā (on the pattern of فُعْلٰىfuʿlā, feminine of اَوْسَطawsaṭ): middle; best. Only once in the Quran: ﴿حٰفِظُوْا عَلَي الصَّلَوٰتِ وَالصَّلٰوةِ الْوُسْطٰى﴾ (Al-Baqarah 2:238)
Form V (tafaʿʿul) تَوَسَّطَ يَتَوَسَّطُ تَوَسُّطًاtawassaṭa yatawassaṭu tawassuṭan: to be in the middle; to intervene between two parties as a mediator (this verb is not used in the Quran).