verb

• (ambitransitive) To build again or anew.
  "The economics of rebuilding all the stations covered by the electrification would be prohibitive, but to help bring home to the Glasgow public that their North Clyde suburban service has been transformed, not merely re-equipped with new trains, stations have at least been associated psychologically with the rolling stock by a common colour scheme."
• (figurative, said of sports teams) To attempt to improve one's performance during a period of struggling.
  "After missing the playoffs for the seventh straight season in a row, the Detroit Red Wings are trying to rebuild."

noun

• (figurative) (said of sports teams) A period during which an attempt is made to improve during a period of struggling.
  "Since they failed to make it to the playoffs after five consecutive seasons, the team has gone through a lengthy rebuild."