النَّكِرَةُ

Indefinite or common is the default state of a noun اسْمٌ

Nouns will be proper or definite / الْمَعْرِفَةُ for the below 7 reasons

أَنَاهُمْهُوَPronouns1
مَكَّةُبِلَالٌأَحْمَدُProper names2
أُلَائِكَذَلِكَهَذَاDemonstrative pronouns3
مَنْمَاالَّتِيالَّذِيRelative pronouns4
الرَّجُلُالْكِتَابُA noun with the definite article الْ5
كِتَابُ حَامِدٍكِتَابُ هَذَاكِتَابُهُA noun with a definite noun as its مُضَافٌ إِلَيْهِ6
يَا رَجُلُيَا وَلَدُA مُنَادَى specified by a نِدَاءٌ (calling)7