Brighid means the "Exalted One" in Irish, and "the Woman" is a figure of intense power in Irish mythological and religious imagination.
February 1st or 2nd is a day claimed by Celtic seasonal thinkers, who called the holiday Imbolc to celebrate Bríd in the form of cailleach-becoming-maiden who collects kindling to make fire in the winter that will warm the spring and make her young again.
This holiday then is understood through the stories of the incredible Brighid. She was the inventor of the mourning songs called caoineadh "keening." In the story, she keens to mourn the death of her son Ruadán and so invents the artform. Brighid's is like the Tibetan ritual of ushering souls to nirvana in the Book of the Dead.
The Irish tradition of making crosses on Imbolc or Lá Fhéile Bhríde is remembered as a Christian ritual and has become that for most Irish people. The spiral of the Brighid cross invokes the North Star and the pattern that the Big Dipper makes in the sky over the course off a year. As the night sky turns around the North Star, the Big Dipper turns through the seasonal year like the hand of a clock.
Brigid is the fire-keeper of that flame of life that mothers tend to so that we don't die in the winter, and so the lines of family are not broken by the trauma of the cold months. In the winter Brighid becomes the cailleach, the woman in agedness, and on Imbolc she collected the kindling of the fires that get her to the spring of regeneration.
Christian interpretation in Ireland makes Brighid into a nun, and children occupy themselves by taking bits of straw and weaving this potential-kindling into the shape of spiraling Brigid's crosses.
Taking up the tradition in its many forms focuses the mind in the meditation of craft, and connects our winter minds mad at the cold to the great wheel that turns and is slowly bringing us into the spring of renewal.
Here's a simple guide on how to make a traditional Brigid's cross: