What's the difference between trip cancellation and trip interruption?

Trip cancellation is designed to cover your prepaid non-refundable trip investment in case you can’t take your trip due to a covered reason (e.g. sickness or injury of a family member, adverse weather conditions) listed in your travel insurance policy. On the other hand, trip interruption provides protection once you have already begun your travel. For example, if you have to cut your trip short or delay it past the expiry date of your policy for a covered reason listed in your policy, or you need to purchase reasonable necessities and toiletries because your baggage is delayed or lost, the trip interruption benefits will reimburse you for such costs up to a dollar amount limit.