It is caused when blood collects at the site of an injury and discolors the skin.
Children under age eight are usually given amoxicillin (Amoxil, Pentamox, Sumox, Trimox) because tetracycline discolors permanent teeth that have not yet come in.
This can stop the watch from looking its best as dirt discolors leather and tarnishes metal.
The word usage examples above have been gathered from various sources to reflect current and historial usage. They do not represent the opinions of YourDictionary.com.