وَالْعَصْرِ

وَالْعَصْرِ is a phrase (شِبْهُ الجُمْلَةِ) consisting of a particle of pulling down (a preposition) and a genitive noun

PhraseParticle / NounNoun Particle
شِبْهُ الجُمْلَةِجَارٌ وَمَجْرُوْرٌاسْمٌ مَجْرُوْرٌحَرْفُ جَرٍّ
PhraseCompoundGenitive NounParticle of pulling down/Preposition
  
by timeوَالْعَصْرِ=الْعَصْرِ+وَ
 by the (passing) timethe (passing) timeby
Surah/Below is the only verse in the holy Quran containing the compoundوَالْعَصْرِ
Verse
103-1By the (passing) timeوَالعَصْرِ