Ilyssa is of Hebrew origin, meaning 'God is my oath'. It is a variant spelling of the more commonly known name Yissel, which itself is a derivative of the male name Isaac. The name Ilyssa gained popularity in the late 20th century and has since been used consistently, though it remains relatively uncommon.
"The name Ilyssa experienced significant popularity peaks between the late 80s and mid-90s, with a high of 41 births in 2004. However, it has since seen a steady decline, with only 5 births recorded in 2021."