vanessa · noun1
From the genus name.
Vanessa · proper noun2
Coined by Jonathan Swift in the 18th century as a pseudonym for a lady friend named Esther Vanhomrigh (or Van Homrigh), an Irish woman of Dutch descent, by taking the Dutch preposition van from her surname and adding -essa (perhaps influenced by the first syllable of Esther).
Etymology from Wiktionary, CC BY-SA 4.0.