Blacken/ˈblækən/ Definition 1 of 3Pro Tip 1/3Physical Change Use 'blacken' to describe something turning dark due to physical changes like burning or dirt. The toast blackened in the toaster. Pro Tip 2/3No Gradual Shade 'Blacken' suggests a significant change in color, not a gradual darkening. The paper quickly blackened around the edges. Pro Tip 3/3Damage Implication Using 'blacken' often implies damage, not just a change in color. The firecracker blackened the mailbox.