Something relatively new, I would say. Based on Kate’s review of the Iron Lady, it originated from Latin and it used to be referred to as something sacred and inviolable.

I chose the third meaning from dictionary.com, mainly because I thought it might be more relevant to use it in our everyday speech. The other two meanings were listed as –

1. Extremely sacred or inviolable.
2. Not to be entered or trespassed upon.

I guess, it could be applied to places of extreme privacy and also certain rules/traditions to be kept?
Would anyone of you have used it before?