This is an old word for manacles or fetters, and cropped up in a book I’m reading at the moment (no, not ‘Fifty Shades of Grey’ – it’s a medieval murder mystery-type thing called ‘Beloved Poison’ by E.S. Thomson which my sister bought me purely because she liked the cover). A not-very-in-depth internet search tells me that ‘gyves’ possibly comes from the Welsh ‘gefyn’ for ‘fetter’ or ‘shackle’, or the Irish ‘geibbionn’ (‘fetters’) or ‘geimheal’ (‘fetter’, ‘chain’, ‘shackle’).
PS Had I remembered to post this yesterday, you would have got a nice fluffy, lovey-dovey word for Valentine’s Day. Although if you’re reading ‘Fifty Shades of Grey’ then maybe manacles are your idea of romance...