Definitions for "Essential service"
a monopoly-supplied service, facility or function that a competitor requires as an input and that it cannot duplicate economically or technically
a service, facility or activity of the Government of Canada that is or will be, at any time, necessary for the safety or security of the public or a segment of the public
A service without which a building would be ‘disabled'. Often applied to the utilities (water, gas, electricity, etc.) it may also include standby power systems, environmental control systems or communication networks.