dew point, wet-bulb, and comfort

Since at least 2013 I have paid attention to dew point, as a measure of comfort. What is it? Definitions vary in wording. The meteorology textbook I'm reading says it is the temperature to which a parcel of air must be cooled to raise the relative humidity of the parcel to 100%. Another definition is that it's the (maximum) temperature an object can be that will cause moisture in the air to condense on it, as mist or dew. These are the same thing, really: the chilly object lowers the temperature of the adjacent air, such that the humidity of the tiny parcels of air hits 100% and moisture condenses.

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