Lee is a spelling that hides more than one surname. In English it is usually a place name from Old English lēah—a clearing, meadow, or pasture—or from villages called Lee, Lea, or Leigh. That is a topographic story: someone lived by the clearing.
In the United States the same four letters also stand for entirely different East Asian surnames, most famously Chinese 李 (Li), often romanized Lee, with its own history and meaning (commonly linked to the plum-tree character). Korean Yi/Ri and other names can appear as Lee too. Census tallies mix these streams. Honesty beats a single cute gloss: ask which branch your family means before you print a one-line motto.