water wing

from the GNU version of the Collaborative International Dictionary of English.

• (Arch.) One of two walls built on either side of the junction of a bridge with the bank of a river, to protect the abutment of the bridge and the bank from the action of the current.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun One of a pair of inflatable plastic bands, normally worn on the upper arms, to help a wearer float in water and learn to swim.
• noun archaic, architecture One of two walls built on either side of the junction of a bridge with the bank of a river, to protect the abutment of the bridge and the bank from the action of the current.