Meaning of the word "there is many a slip twixt cup and lip" in English

What does "there is many a slip twixt cup and lip" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

there is many a slip twixt cup and lip

US /ðɛr ɪz ˈmɛni ə slɪp twɪkst kʌp ænd lɪp/
UK /ðɛər ɪz ˈmɛni ə slɪp twɪkst kʌp ænd lɪp/
"there is many a slip twixt cup and lip" picture

Idiom

even when a plan seems certain to succeed, something can still go wrong before it is finished

Example:
The contract is almost signed, but there is many a slip twixt cup and lip.
I thought I had won the race, but there is many a slip twixt cup and lip as I tripped at the last hurdle.