What is the meaning of Coucou?

Alternative form of coo-coo (“Barbadian food”).

cuckoo

cuckoo (the bird)

cuckoo (the cry of the bird)

cuckoo clock

cowslip (flower)

old plane; old crate; rust bucket; any old vehicle, especially one that is rickety

cuckoo; the call of the cuckoo

peekaboo

hiya, hey; an informal greeting

an informal goodbye, bye-bye

toad

cuckoo

striped wrasse

Source: wiktionary.org