What is the meaning of span?

noun

• The complete duration of something.
  • usage: "the job was finished in the span of an hour"
• The distance or interval between two points.
• Two items of the same kind.
  • synonyms: couple, pair, twosome, twain, brace, yoke, couplet, distich, duo, duet, dyad, duad
• A unit of length based on the width of the expanded human hand (usually taken as 9 inches. )
• A structure that allows people or vehicles to cross an obstacle such as a river or canal or railway etc..
  • synonyms: bridge
• The act of sitting or standing astride.
  • synonyms: straddle

verb

• To cover or extend over an area or time period.
  • usage: "Rivers traverse the valley floor, "The parking lot spans 3 acres"; "The novel spans three centuries"
  • synonyms: cross, traverse, sweep