What does Kingston mean?
An English place name and surname meaning 'king's town' or 'king's settlement' (Old English 'cyning' + 'tun'). A place-name origin referencing a king rather than meaning 'king' outright.
What does King mean?
The English vocabulary word 'king' (Old English 'cyning') used directly as a given name. A transferred surname/word-name rather than an etymological 'king' name from another root.