water wings

noun
  1. 1

    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.

  2. 2

    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.

Source: https://en.wiktionary.org/wiki/water%20wing, https://en.wiktionary.org/wiki/water%20wings