Serratura vs. lucchetto

The Italian words 'serratura' and 'lucchetto' both refer to locks, but they are used for different types of locking mechanisms.

Serratura

'Serratura' refers to a lock that is typically built into a door or furniture piece. It is a fixed locking mechanism that requires a key to open.
La serratura della porta d'ingresso è rotta.
(The front door lock is broken.)
Ho dimenticato le chiavi e non posso aprire la serratura.
(I forgot my keys and can't open the lock.)
Questa cassaforte ha una serratura molto sicura.
(This safe has a very secure lock.)

Lucchetto

'Lucchetto' refers to a padlock, which is a portable lock with a shackle that can be passed through an opening and then snapped shut.
Ho messo un lucchetto sulla mia bicicletta.
(I put a padlock on my bicycle.)
Il cancello del giardino è chiuso con un lucchetto.
(The garden gate is closed with a padlock.)
Per sicurezza, usa un lucchetto per chiudere la tua valigia.
(For safety, use a padlock to lock your suitcase.)

Summary

While both 'serratura' and 'lucchetto' are types of locks, 'serratura' is typically a fixed lock built into doors or furniture, while 'lucchetto' is a portable padlock that can be used on various items. 'Serratura' is commonly found on doors, drawers, and safes, whereas 'lucchetto' is often used for bicycles, gates, lockers, and luggage.