Definition of "thonk" []

• An obsolete or dialectal form of thank.

The Century Dictionary (Public Domain)

• "PC sounds quite loveable and more my style; plus the "thonk, thonk" of the tennis balls puts me in a summer mood..."
• "In two years I can thonk of about three or four occasions in 4700 blogposts where that as happened."
• "Just thonk of the additional permanent government employees required to manage these programs."