• إِرْصَاد
• رَصَد
• مِرْصَاد
• مَرْصَد

Appears 6 times in the Quran.

1. 9:5 فَإِذَا ٱنسَلَخَ ٱلْأَشْهُرُ ٱلْحُرُمُ فَٱقْتُلُوا۟ ٱلْمُشْرِكِينَ حَيْثُ وَجَدتُّمُوهُمْ وَخُذُوهُمْ وَٱحْصُرُوهُمْ وَٱقْعُدُوا۟ لَهُمْ كُلَّ مَرْصَدٍ فَإِن تَابُوا۟ وَأَقَامُوا۟ ٱلصَّلَوٰةَ وَءَاتَوُا۟ ٱلزَّكَوٰةَ فَخَلُّوا۟ سَبِيلَهُمْ إِنَّ ٱللَّهَ غَفُورٌ رَّحِيمٌ

   So when the sacred months have passed away, then slay the idolaters wherever you find them, and take them captives and besiege them and lie in wait for them in every ambush, then if they repent and keep up prayer and pay the poor-rate, leave their way free to them; surely Allah is Forgiving, Merciful.
   

2. 9:107 وَٱلَّذِينَ ٱتَّخَذُوا۟ مَسْجِدًا ضِرَارًا وَكُفْرًا وَتَفْرِيقًۢا بَيْنَ ٱلْمُؤْمِنِينَ وَإِرْصَادًا لِّمَنْ حَارَبَ ٱللَّهَ وَرَسُولَهُۥ مِن قَبْلُ وَلَيَحْلِفُنَّ إِنْ أَرَدْنَآ إِلَّا ٱلْحُسْنَىٰ وَٱللَّهُ يَشْهَدُ إِنَّهُمْ لَكَٰذِبُونَ

   And those who built a masjid to cause harm and for unbelief and to cause disunion among the believers and an ambush to him who made war against Allah and His Messenger before; and they will certainly swear: We did not desire aught but good; and Allah bears witness that they are most surely liars.
   

3. 72:9 وَأَنَّا كُنَّا نَقْعُدُ مِنْهَا مَقَٰعِدَ لِلسَّمْعِ فَمَن يَسْتَمِعِ ٱلْءَانَ يَجِدْ لَهُۥ شِهَابًا رَّصَدًا

   And that we used to sit in some of the sitting-places thereof to steal a hearing, but he who would (try to) listen now would find a flame lying in wait for him:
   

4. 72:27 إِلَّا مَنِ ٱرْتَضَىٰ مِن رَّسُولٍ فَإِنَّهُۥ يَسْلُكُ مِنۢ بَيْنِ يَدَيْهِ وَمِنْ خَلْفِهِۦ رَصَدًا

   Except to him whom He chooses as a messenger; for surely He makes a guard to march before him and after him,
   

5. 78:21 إِنَّ جَهَنَّمَ كَانَتْ مِرْصَادًا

   Surely hell lies in wait,
   

6. 89:14 إِنَّ رَبَّكَ لَبِٱلْمِرْصَادِ

   Most sure!y your Lord is watching.