What is the meaning of build up?

verb

• Enlarge, develop, or increase by degrees or in stages.
  • usage: "build up your savings"
• Form or accumulate steadily.
  • usage: "Resistance to the manager's plan built up quickly"; "Pressure is building up at the Indian-Pakistani border"
  • synonyms: work up, build, progress
• Prepare oneself for a military confrontation.
  • usage: "The U. S. Is girding for a conflict in the Middle East"; "troops are building up on the Iraqi border"
  • synonyms: arm, fortify, gird
• Bolster or strengthen.
  • usage: "We worked up courage"; "build up confidence"; "ramp up security in the airports"
  • synonyms: work up, build, ramp up
• Change the use of and make available or usable.
  • usage: "develop land"; "The country developed its natural resources"; "The remote areas of the country were gradually built up"
  • synonyms: develop