To top and tail is to cut off the top and bottom ends of a fruit or vegetable before cooking or eating it — removing the stem end and the root or blossom end. The ends are typically tougher, woodier, or less pleasant than the middle: the tops of green beans, the tails of carrots, the stem caps of strawberries. It is basic preparation, done with a knife or by snapping, and it also tidies the appearance of the prepared vegetable. The trimmed ends need not be wasted — they go into stocks, compost, or animal feed. The phrase is a fixture of British cookery writing, where top and tail the beans is as standard an instruction as chop the onion.