If you’ve heard the word bard, it was probably in English class. William Shakespeare has been known as "The Bard" since the nineteenth century, but the word has a much older history, and, when it's not capitalized, it simply means "lyric poet."
In civilizations without written histories, poets and singers were the ones to spread the word from place to place and across generations. In ancient and medieval Gaelic societies, the professional storytellers were called bards (or bardds, in Wales). Irish bards were part of a chieftain's household, and their job was to record and proclaim the exploits of their lord — although a bard might also compose blistering satires if he was displeased with his employer.