IPA: /ˈɑːsənəl/
KK: /ˈɑr.sə.nəl/
A place where weapons and military equipment are stored or made, or a collection of weapons.
The army has a large arsenal of advanced weaponry.
Arsenal → The word originates from the Italian 'arsenale', which comes from the Arabic 'dār al-ṣināʿa' (meaning house of manufacture or workshop). It refers to a place where weapons and military equipment are stored or manufactured.
Think of a 'workshop' ('dār al-ṣināʿa') where weapons are made and stored — that's why an arsenal is a place for military supplies.