Modern invented name, possibly meaning valley or lake
Thailyn is a modern American coinage, likely created by blending the prefix 'Thai' with the popular suffix 'lyn'. While it lacks a singular historical root, it is often associated with the Welsh 'lyn' meaning lake or the English 'thale' referring to a valley.
Less common today
Thailyn isn't in the latest US Top 1000. It last peaked at #11,270 in 2017.
US births per 5-year period, 1990βpresent (SSA data).