Any start below an oil temp of approx 165-175 deg F is a cold start, at least from the standpoint of the engine producing and accumulating corrosion products. Once at normal oil temps 175-185 deg F the "damage" from cold starting/warm up is essentially over.
The car mfg's test their engines & oils in the 130-150 deg (oil temp) corrosion range for X number of hours to see how well the oil holds up. At colder temps the oil's cold viscosity is supplying a strong benefit. Once that's gone, and before normal oil temps, and before the oil's add package is fully functional when hot, is the range of 130-150 deg that you want to minimize. To me, cold start means conditions ripe for engine corrosion and wear.