1
general::
An instantaneous attraction to someone or something. For example, With Peter and Constance, it was a case of love at first sight, or When Dave saw that car, it was love at first sight. This expression was already used by Chaucer for romantic attraction in Troilus and Cressida: "She loved right from the first sight." The transfer to objects dates from the first half of the 1900s.
American Heritage Idioms
2
general::
Phrase(s): love at first sight
Fig. love established when two people first see one another. • Bill was standing at the door when Ann opened it. It was love at first sight. • It was love at first sight when they met, but it didn’t last long.
McGrawhill's American Idioms And Phrasal Verbs