Absolute uncertainty is defined as the total amount by which a measured value may differ from the actual value, contrasting with fractional uncertainty, which is the ratio of absolute uncertainty to the measured value. The discussion highlights a preference for the term "systematic error" over "systematic uncertainty," suggesting that total error comprises both systematic and random components. In repeated measurements of the same quantity, these errors can be interpreted as either fractional or absolute. When measuring different quantities, the nature of these errors may change, with systematic errors potentially remaining constant in fractional terms while random errors may be constant in absolute terms. The conversation emphasizes the complexity of understanding and categorizing measurement errors.