**Bid‘ah(, it can be defined as all things invented or acts done for which there is no precedent. It can be either related to the dealings and affairs of worldly life, such as inventing planes, cars, trains, electrical devices, cooking utensils, air conditioners used for warming and cooling, and even war machines such as bombs, submarines, tanks, and other objects made to serve people in this world.

**Such things in themselves are permissible and there is no sin in inventing them. As for the purpose of inventing and using them; if they are used in beneficial matters, they are good; and if they are meant for evil purposes, such as sabotaging, destruction, and corruption on earth, they are evil and affliction.Bid‘ah can also be in religion. It may fall under ‘Aqidah (creed) or ‘Ibadah (worship), whether in words or actions, such as denying predestination, (Part No. 2; Page No. 453) building Masjids (mosques) and shrines over graves, reciting the Qur'an over the dead, and celebrating the Mawlid (birthdays) to commemorate dead or renowned people, seeking the help of anyone other than Allah, and circumambulating shrines.

**All these acts and their like are deviation from what is right, because the Prophet (peace be upon him) said: Beware of newly-invented matters (in religion), for every newly-invented matter is a Bid‘ah, and every Bid‘ah is a Dalalah (deviation from the right). Nonetheless, some of these are acts of major Shirk (associating others with Allah in His Divinity or worship that takes the Muslim out of Islam), such as seeking help from a source other than Allah in things that only Allah is able to do, slaughtering sacrificial animals and vowing to other than Allah (Exalted be He), and other acts of worship that belong to Allah.

source:
https://www.al-feqh.com/en/meaning-of-good-and-bad-bid%E2%80%98ah