Actually, now I recall them being referred to as "acorn" lights, though they used look more like acorns back in the incandescent days before they were retrofitted with the rounder fixtures with metal halide bulbs. There are several versions of the cobra head,
the most common of which in Toronto look somewhat cheap and inelegant with their extreme upward slope, bulky head, and grey arm. Among Modernist styles, I prefer
the Gardiner's original cobra heads (though they'd probably look inappropriate in a non-expressway setting),
the Financial District's black lights, and
arc lights, though the latter are more common in Montreal and certain American cities where overhead wires are extensively buried.