Syrup comes through Middle English sirup and Anglo-French sirop from Medieval Latin syrupus, ultimately from Arabic sharāb.
Sirup is also a current spelling variant. The cards use its Middle English appearance and select syrup for the modern spelling.
Sources
- Merriam-Webster: syrup
Word History supplies the five selected stages; Kids Definition explicitly lists sirup as a variant.
- Anglo-Norman Dictionary · sirop
Meanings of the older forms on the word path.
- Digital Dictionaries of South Asia · steingass query.py
Meanings of the older forms on the word path.
- logeion.uchicago.edu · sirupus
Meanings of the older forms on the word path.
- Online Etymology Dictionary · syrup
Meanings of the older forms on the word path.