adumbration (n.) Look up adumbration at Dictionary.com
1550s, "faint sketch, imperfect representation," from Latin adumbrationem (nominative adumbratio) "a sketch in shadow, sketch, outline," noun of action from past participle stem of adumbrare "to cast a shadow, overshadow," in painting, "represent (a thing) in outline," from ad- "to" (see ad-) + umbrare "to cast in shadow," from PIE root *andho- "blind; dark" (see umbrage).