Q: The etymological appendix at the end of my dictionary suggests that “think” and “thank” are related. It has taken me a long time to connect my thinking and my thanking, especially to think before I thank, and thank before I think. If you have anything to share, I’d be thankful. I’m already thinkful in anticipation!
A: “Think” and “thank” are indeed etymologically related, and have as a common ancestor the ancient Indo-European root tong, meaning to feel or think.
This prehistoric root was the source of a proto-Germanic word, reconstructed as thankaz, which gave us the Old English words thencan (to think, to conceive in the mind), thoht (thought), thanc (meaning thought, good will, gratitude), thancian (to thank), and thyncan (to seem or appear).
The last word, thyncan, gave us the now-obscure “methinks” (literally, “it seems to me”). So, methinks, thinking and thanking sprang from the same thoughtful source!
By the way, our modern verb “think” was once two separate Old English verbs: thyncan (to seem or appear) and thencan, whose original meaning, according to the Oxford English Dictionary, may have been “to cause (something) to seem or appear (to oneself).” In Middle English, the two verbs merged into one.
Thanks for your thinkful question.