1. a line on a map connecting points of equal value or intensity of a particular phenomenon
Usage: technical; geography and meteorology
2. a signature or handwriting sample that is identical or nearly identical to another
Usage: forensic; rare

Examples

• Meteorologists use isographs to show temperature variations across a region.
• The weather map displayed isographs connecting areas of equal rainfall.
• An isograph of pressure systems helps forecasters predict storm movement.
• The document examiner compared the isographs to verify the authenticity of the signature.