Torcia vs. fiaccola

Both 'torcia' and 'fiaccola' refer to handheld lighting devices with flames, but they have distinct uses and connotations in Italian.

Torcia

'Torcia' typically refers to a modern, portable light source, often battery-powered, but can also mean a traditional flame torch.
Ho usato la torcia del cellulare per trovare le chiavi al buio.
(I used the phone's flashlight to find the keys in the dark.)
Il guardiano notturno portava una torcia per illuminare il percorso.
(The night watchman carried a torch to light the path.)

Fiaccola

'Fiaccola' specifically refers to a traditional flame torch, often associated with ceremonies, sports events, or symbolic uses.
L'atleta portava la fiaccola olimpica durante la cerimonia di apertura.
(The athlete carried the Olympic torch during the opening ceremony.)
I manifestanti marciavano con le fiaccole per le strade della città.
(The protesters marched with torches through the city streets.)

Summary

While 'torcia' can refer to both modern flashlights and traditional flame torches, 'fiaccola' is specifically used for ceremonial or symbolic flame torches. 'Torcia' is more common in everyday contexts, whereas 'fiaccola' is often associated with formal or historical settings.