What is needed to certify an aerodrome as an airport in Canada?
Original Answer
Aerodrome
It is an area where:

aircraft land
aircraft take off

Runway may not be present (in case of a water aerodrome).
Airport1
By definition2, an airport is an aerodrome with facilities for commercial aviation flights to take off and land
It is an aerodrome which has:

facilities to store and maintain aircraft
at least one designated operational landing/takeoff area (runway or helipad)
hangars
terminals
fixed base operators
airport aprons
air traffic control centers
passenger facilities (restaurants and lounges etc.)
emergency services
customs3
immigration3

Edit
I noticed that the question is updated to be only for Canada. In that case, airport requires the following:


have a safety management system in place
comply with airport safety standards and security requirements


Further reading
Aerodrome
Airport
Airport Design and Engineering Standards (by FAA)
Aerodrome Standards (PDF by ICAO)

1: Not all airports must have all of these to qualify as an airport.
2: I could not find specific regulations which define an airport.
3: In case of an international airport