IPA: /ˈstrɔːŋbɒks/
KK: /ˈstrɔŋˌbɑks/
A sturdy box or safe used to store valuable items securely.
He kept his important documents in a strongbox to protect them from theft.
Strongbox → It is formed from "strong" (from Old English "strang", meaning having power or strength) and "box" (from Old English "box", meaning a container). The word "strongbox" refers to a secure container that is strong enough to protect valuable items.
Think of a 'strong' container that keeps your valuables safe — that's what a strongbox is.
No commonly confused words.