思: Thought, intellect. In names, it often signifies quick thinking, sharp wit, and intelligence.
杜: Du Kang, Du Fu. The character "Du" refers to the sweet pear tree, as stated in the "Shuowen Jiezi" dictionary: "The male is called 'Tang', and the female is called 'Du'."
Meaning: Si signifies thought and remembrance, symbolizing wisdom and emotion; Du signifies the pear tree or obstruction, symbolizing resilience and focus.