In botany, the Latin word allium refers to a genus of plants that includes garlic, onions, and leeks. Alliaceous—pronounced alley ay shus—is the adjective formed from this Latin word and it can be applied to anything, including food or breath, that smells of garlic or onions. In the Middle Ages in southern Europe, food tended to be alliaceous because garlic helped disguise the fact that warm temperatures had turned some of the ingredients bad.