This is a cloche. Cloche means bell in French. I believe a cloche was originally referred to as a small glass dome used to force plants to bloom (like a mini green house). But in decor terms, it's usually a display (raised on a stand) under glass.
oil can +vintage wood spool + rolls of crochet thread - awesome DIY display for brooches/pins! Very clever, but I like the idea of using a skein of yarn for color. (check out other wedding accessories at "theweddingpicker" Etsy shop!