Carosello vs. giostra
The Italian words 'carosello' and 'giostra' both refer to amusement park rides, but they have distinct uses and connotations in Italian.
Carosello
'Carosello' primarily refers to a carousel or merry-go-round, but it can also mean a sequence or series of events.
I bambini adorano fare un giro sul carosello.
(The children love to take a ride on the carousel.)
Il carosello pubblicitario in TV è finito.
(The TV advertising carousel has ended.)
La sua vita è un carosello di emozioni.
(His life is a carousel of emotions.)
Giostra
'Giostra' also means carousel or merry-go-round, but it can refer to various types of fairground rides and has historical connotations related to jousting.
La giostra dei cavalli è l'attrazione preferita dei bambini al luna park.
(The horse carousel is the children's favorite attraction at the amusement park.)
Nel Medioevo, i cavalieri partecipavano alle giostre.
(In the Middle Ages, knights participated in jousts.)
Quella giostra mi fa venire il mal di testa.
(That ride gives me a headache.)
Summary
While 'carosello' and 'giostra' can both refer to carousels, 'carosello' is more specific to merry-go-rounds and can metaphorically describe sequences. 'Giostra' has a broader application to fairground rides and retains historical connections to jousting events.