A sardine is a very small, oily fish. You might like to eat sardines on toast for lunch. If you do, we suggest an after-lunch mint may be in order.
Sardines are most often bought canned, lined up in rows in little tins. The word sardine is actually a general term — it refers to a type of fish, most often a small herring, while a slightly larger one is sometimes called a pilchard. The phrase "packed like sardines," describing people crowded together in a tight spot like an elevator or a subway car, comes from the way sardines look in cans. The word itself comes from the Mediterranean island Sardinia.