The word(s) "plains" appears 4 time(s) in 4 verse(s) in Quran in Mohsin Khan translation.

(1) And remember when He made you successors after 'Ad (people) and gave you habitations in the land, you build for yourselves palaces in plains, and carve out homes in the mountains. So remember the graces (bestowed upon you) from Allah, and do not go about making mischief on the earth."

(2) It is He Who made the sun a shining thing and the moon as a light and measured out for it stages that you might know the number of years and the reckoning. Allah did not create this but in truth. He explains the Ayat (proofs, evidence, verses, lessons, signs, revelations, etc.) in detail for people who have knowledge.

(3) Allah is He Who raised the heavens without any pillars that you can see. Then, He rose above (Istawa) the Throne (really in a manner that suits His Majesty). He has subjected the sun and the moon (to continue going round), each running (its course) for a term appointed. He manages and regulates all affairs; He explains the Ayat (proofs, evidence, verses, lessons, signs, revelations, etc.) in detail, that you may believe with certainty in the meeting with your Lord.

(4) Indeed Allah has heard the statement of her (Khaulah bint Tha'labah) that disputes with you (O Muhammad صلى الله عليه وسلم) concerning her husband (Aus bin As-Samit), and complains to Allah. And Allah hears the argument between you both. Verily, Allah is All-Hearer, All-Seer.