By request of @Maxmustang
ETOPS, or Extended range operation with two engine aircraft is a ICAO rating, given to aircraft allowing them to fly long distance routes over remote areas eg Water. The first ratings were given out in the 70s, which permitted rated aircraft to fly up to 120 minutes away from a capable diversion airport, over the usual 60 minute. The A300 and 767 became early ETOPS hits, and were popular with airlines, causing tri-jets to die off and 747 production to slow.
Currently certifications up to ETOPS-370 (370 mins away from an alternate aircraft) can be given, and also 4 engine aircraft are now included. The A340 has an option for a ETOPS-240 rating, and all versions of the 777 have ETOPS-330. The A350 has been given the maximum rating of ETOPS-370.
ETOPS-120 means that aircraft can fly over 95% of the world: