المعنى الاصطلاحي :

Allah's praising of the Prophet before the Higher Assembly of angels.

الشرح المختصر :

"As-salāh ‘ala an-Nabyy" (conferring blessings upon the Prophet) is a great act of worship. It is an honor from Allah, the Exalted, for Prophet Muhammad, the last of the messengers and prophets. There are different formulas for this "salāh": - "Salla Allahu ‘alayhi wa sallam" (may Allah's peace and blessings be upon him). - The minimum to say: "Allahumma salli ‘ala Muhammad" (O Allah, confer blessings upon Muhammad). - The best version is "As-salāh al-Ibrāheemiyyah", which is recited in prayer in the second half of the "tashahhud": "Allahumma salli ‘ala Muhammad wa ‘ala āli Muhammad, kama sallayta ‘ala āli Ibrāheem, innaka Hameedun Majeed. Allahumma bārik ‘ala Muhammad wa ‘ala āli Muhammad, kama bārakta ‘ala Ibrāheem, innaka Hameedun Majeed." (O Allah confer blessings upon Muhammad and the family of Muhammad as You conferred blessings upon the family of Ibrāhim. Indeed, You are Praiseworthy and Glorious. O Allah bless Muhammad and the family of Muhammad as You blessed Ibrāhim. Indeed, You are Praiseworthy and Glorious.) It has other wordings too. "O Allah confer blessings upon him" means: praise him in the Higher Assembly; i.e. in the presence of the angels who are nearest to Allah.