What does a 'cold start' refer to in engine operation?

A 'cold start' refers to the process of starting an engine after it has been turned off and has had time to cool down sufficiently. When an engine is cold, the oil may thicken, and various components may not be operating at optimal temperatures, which can affect performance. This situation is often addressed by allowing the engine to warm up after starting, ensuring that the oil circulates properly and that components function effectively as their temperatures rise.

In contrast, the other options describe scenarios that do not accurately reflect the term 'cold start.' Starting an engine without maintenance does not specifically relate to its operational temperature, starting without sufficient fuel pertains to fuel delivery issues, and starting an engine while it is still hot is contrary to the concept of a 'cold start.' Thus, focusing on the cooling aspect of the engine after it has been turned off clarifies the purpose and implications of a cold start in engine operation.