From Peter Leithart's Gratitude: An Intellectual History (Baylor UP, 245n49):
The Hebrew word for thanksgiving, todah, derives from the verb yadah, "praise," the root of the name Judah. Etymologically, the words for "praise" and "thanksgiving" are connected, and the verb form yadah is used regularly throughout the Hebrew Bible, translated as "thank," "praise," or "confess" depending on the context. The Psalms do not neatly divide into psalms of praise and psalms of thanksgiving, into psalms that celebrate Yahweh's character and attributes in themselves and psalms that celebrate Yahweh's acts on behalf of his people. Thanks and praise merge into one another in a theologically significant way, a sign that for Israel God's character is revealed in history and the world.See here for another quote from the book.