المعنى الاصطلاحي :

It is to publicly practice and call to a ritual from the rituals of Islam after it has been neglected or abandoned.

الشرح المختصر :

"Ihyaa as-Sunnah" (reviving the Sunnah) means to publicly practice acts of Islam that have been abandoned and are rarely practiced by the people. This is done by performing these acts and calling others to them, especially the Sunnah acts that have been neglected by the people due to their ignorance of them or their laziness to do them. What is meant by Sunnah here is the Islamic Shariah in general, as well as all the statements, actions, approvals, and descriptions authentically attributed to the Prophet, may Allah's peace and blessings be upon him. This phrase - "ihyaa as-Sunnah" - is often paired with another phrase, which is abolishing "bid‘ah" (religious innovation). An example of reviving the Sunnah is a person who orders men to grow their beards in a Muslim country where it has become a common practice to shave it. By doing this, that person has revived a great act of the Sunnah in that country.