surfing

Concise Oxford English Dictionary © 2008 Oxford University Press:
surf/sɜːf/

▶noun the mass or line of foam formed by waves breaking on a seashore or reef. ▶verb

• 1 stand or lie on a surfboard and ride on the crest of a wave towards the shore.

  ■ informal ride on the roof or outside of a fast-moving vehicle, typically a train, for excitement.

• 2 move from site to site on (the Internet).

– derivatives
surfer noun,
surfing noun,
surfy adjective.

– origin C17: appar. from obs. suff, of unknown origin, perh. influenced by the spelling of surge.