A Broadstrike is a coin struck without the restraining collar that maintains the diameter and shape of a coin in addition to imparting reeding or sometimes other edge devices. The absence of a collar allows the coin to spread beyond its normal confines. When the planchet is centered over the anvil die, it is called a Centered Broadstrike. When the coin appears uncentered, the struck coin shows some area of the planchet to one side or another but contains the entire coin design, it's called an Uncentered Broadstrike.

This 1964 Half-Penny is a Centered Broadstrike. Coin courtesy of Mark Longas of MI.

This 1817 British Shilling is an Uncentered Broadstrike. Coin courtesy of Mark Longas.