حَرْفُ جَوَابٍ
is a particle of answering questions.
نَعَمْ means Yes
لَا means No
Examples :-
1) أَهَذَا مَسْجِدٌ ؟ (Is this a masjid?)
نَعَمْ، هَذَا مَسْجِدٌ (Yes, this is a masjid)
2) أَهَذَا حِصَانٌ ؟ (Is this a horse?)
لَا، هَذَا حِمَارٌ (No, this is a donkey)
