It could mean a million things, depending on the context, but in literature it usually is a form of sonnet. It is the way the meter and rhyme sheme go. Just google shakespearean sonnet rhyme scheme...
The word "gi" from Shakespearean English means "give". In Act 1 Scene 2 of Shakespeare's Romeo and Juliet, the servant says "God gi' ye godd'en". Which is translated to "God give you good evening"....