The Great Gatsby, peculiarly unreal feeling

I'd like to know the meaning of "peculiarly" in the following excerpt from the chapter Six of The Great Gatsby. Does it mean "strangely" or "especially", "uniquely"

“Perhaps you know that lady.” Gatsby indicated a gorgeous, scarcely human orchid of a woman who sat in state under a white plum tree. Tom and Daisy stared, with that peculiarly unreal feeling that accompanies the recognition of a hitherto ghostly celebrity of the movies.

Thank you.