Aground means stuck on the bottom in shallow water. When a ship runs aground, its hull scrapes or settles onto sand, mud, or rocks beneath the surface, leaving it unable to move forward.

Picture a large sailboat approaching the shore: if the captain misjudges the water's depth, the boat might suddenly run aground, its keel digging into the sandy bottom with a grinding noise. The ship sits there, tilted and helpless, until the tide rises or tugboats arrive to pull it free.

Running aground can happen to any vessel, from kayaks in rocky streams to massive cargo ships that drift off course in fog. Sometimes ships run aground during storms, when powerful waves push them toward shore. Other times, navigational errors or equipment failures lead a ship into water that's too shallow.

The word specifically describes being stuck on the bottom of a body of water. A boat caught in seaweed or tangled in a fishing net might be stuck, but it isn't aground. A canoe wedged on a sandbar, however, definitely is aground. Experienced sailors study charts carefully and watch their depth gauges to avoid running aground, since freeing a grounded vessel can take hours, damage the hull, or even require removing part of the cargo to make the ship lighter.