Below I have included a snippet from a very informative article which resides on the druidry.org website. It takes the time to better explain the special day and seasonal festivals and how they are represented. Enjoy!
“Deeper Into Lughnasadh
Also known as Lammas, or First Harvest, the name of this festival as Lughnasadh is Irish Gaelic for “Commemoration of Lugh”. Some authors give the meaning as marriage, gathering or feast (in the name of) of Lugh. The meaning remains basically the same: Lugh is the Deity of Lughnasadh, and there is a feast.
Although Lugh gives his name to this festival, it is also associated with Lugh’s foster mother Tailtiu, who is said to have cleared the way for the introduction of agriculture in Ireland, thus linking Lughnasadh to the land and the harvest.
The modern Irish Gaelic name for the month of August is Lúnasa. In Scottish Gaelic Lunasda means the 1st of August.
One of several historic sources for the four Celtic fire festivals Imbolc, Bealtaine, Lughnasadh und Samhain is the early medieval Irish tale “Tochmarc Emire” (The Wooing of Emer), which is part of the Ulster Cycle. In the form we know it today it was written in the 10th or 11th century CE, but it is safe to assume that this tale – like so many others – contains a much older nucleus.
The tale narrates how the hero Cú Chulainn is courting Emer. He receives several tasks to fulfill, one of them being that he must go without sleep for one year. As Emer utters her challenge, she names the four major points of the Irish-Celtic year, as they are also mentioned in other Irish sources. Doing this, she does not use the solar festivals, nor Christian ones, which were certainly well known and established by the 10th century. Instead Emer choses the first days of each season.
One of these days is Lughnasadh, marking the beginning of fall. It takes place on the 1st of August, a date internationally agreed upon, or on the day of the full moon next to this date, if you want to celebrate when the ancient Celts probably did.
Since the Celtic day started with sunset, the celebration takes place on the evening before the calendaric date.
Lughnasadh marks the beginning of the noticeable descent of the Sun into the darkness of winter. From the connection between the Earth (female principle) and the Sun (male principle), the marriage of the Sky Father (Sun God) with the Earth Mother we celebrated at Bealtaine, emerge the fruits of the first harvest of the year. Lughnasadh is a time of joy about the first fruits. It is also a time of tension, because the dark days of winter are coming nearer, and most of the harvest is not brought in and stored away yet.
The God of the harvest is the Green Man (also known as John Barleycorn). He sacrifices himself every year in order to enable human life on Earth. In some areas his death is mourned with wreaths decorated with poppies or cornflowers.
The grain is cut, part of it goes into bread and nutrition, another part is stored away and used as seeds next spring, to create new life. Looking at that, thoughts about sacrifice, transformation, death and rebirth are also part of Lughnasadh.”