1. the foremost part of an advancing army or naval force
Usage: military
2. the leaders of a movement or the forefront of new developments

Examples

• The vanguard of the army crossed the river at dawn.
• She was in the vanguard of the civil rights movement.
• This company is in the vanguard of technological innovation.
• The vanguard troops encountered heavy resistance.
• Artists in the vanguard often face criticism from traditionalists.
• The research team is at the vanguard of cancer treatment.
• Revolutionary ideas often emerge from the vanguard of society.