Eid or 'id is the Arabic word for Celebration or Festival
The Eid or 'id العيد (also عيد, pl. a'yaad اعياد) is the Arabic word for a Celebration.
Muslims have two major Celebration days:
'Id al-Adha عيد الأضحى the Sacrifice Feast on the 10th Day of Dhu-l Hijja (the last hijri month):
It honors the willingness of Abraham (Ibrahim) to sacrifice his son, as an act of submission to God's command, before God then intervened, through his angel Gabriel (Jibra'il) and informs him that his sacrifice has already been accepted. The meat from the sacrificed animal is preferred to be divided into three parts. The family retains one third of the share; another third is given to relatives, friends and neighbors; and the remaining third is given to the poor and needy.
and
'Id al-Fitr عيد الفطر which is the Breaking the Fast Feast at the first day of Shawwal (the 1oth hijri month) which marks the end of the month of fasting Ramadan