A term from linguistics, meaning they show in the similarity of their form that they derive from a common parent. Thus Spanish Some cognates are less obvious because more distant. Go back far enough into the pedigrees of the Indo-European languages, and English "I," French "je," German "Ich," Spanish "yo," Italian "io," and Latin "ego" all appear related.

From the Guide to Literary Terms by Jack Lynch.
Please send comments to Jack Lynch.
Note: This guide is still in the early stages of development.
Three question marks mean I have to write more on the subject. Bear with me.