A latin term that means “about minimal things” is - ironically - taking on a huge significance for Canada in the re-negotiation of NAFTA. The de minimis level -also referred to as the low value threshold - refers to the value below which duty and taxes are not charged.
Currently, most items valued under $800 US can be imported duty free to the USA. Under the new USA Canada Free Trade agreement (USMCA) imports to Canada valued over $40 CAD are subject to duty and taxes. Express shipments valued under $150 CAD can be imported duty free (but are subject to sales tax).