流行

liúxíng
  1. (of a contagious disease etc) to spread
  2. to propagate
  3. (of a style of clothing, song etc) popular
  4. fashionable

CEDICT

Entry Composition

1 流 liú
  1. to flow
  2. to disseminate
  3. to circulate or spread
  4. to move or drift
  5. to degenerate
  6. to banish or send into exile
  7. stream of water or sth resembling one
  8. class, rate or grade
2 行 xíng
  1. (bound form) to walk; to go; to travel
  2. (literary) trip; journey; visit
  3. (bound form) temporary; makeshift
  4. (bound form) current; in circulation
  5. (bound form) to do; to perform
  6. capable; competent
  7. all right; OK!; will do
  8. behavior; conduct (Taiwan pr. xìng)
  9. (literary) about to; soon