Based upon where you are from, different countries have different terms for "storm drain".

Depending on where you are from, different countries have different terms for "storm drain".
Accordingly to Wikipedia, a storm drain is essentially a tunnel that carry runoffs (rain) from urban areas. For a layman, it helps to think along the line of sewage system functions beneath our cities.
In the states, this is also known as "storm drain" or "storm sewer".
In the UK, this is actually often called "surface water drain" or "surface water sewer".
In drain covers outdoor and New Zealand, it is typically referred to as "stormwater drain".
And there it is, the very next time you hear someone mentioning "storm drain", "storm sewer", "surface water drain","surface water sewer" and "stormwater drain", congratulations, you know they talk about the same thing.
Functions of storm drain include draining excess water (rain or storm water) and ground water from pavement, streets and carparks into rivers and streams in order to avoid flooding.
Although storm drains do a amazing job of draining excess water from the urban areas, the inlets are essentially openings where left uncovered can pose a danger to pedestrians. Left uncovered, rubbish will enter the storm drains and cause choking which can eventually trigger flooding.
To guarantee storm drains serve their purposes while minimizing the dangers posed to pedestrians and to prevent choking of the drains, drain covers (gratings) are used to cover the inlets (openings) of the storm drains to achieve the two purposes.
At Jonite, we specialize in steel reinforced drain covers (gratings) which cover your storm drains while preserving the aesthetic aspects of the architecture around the drain covers.