Resting metabolic rate is the combination of and energy required to perform sedentary activities such as sitting, reading, typing, and digesting food.

Resting metabolic rate is the combination of basal metabolic rate and energy required to perform sedentary activities such as sitting, reading, typing, and digesting food.
The basic metabolism refers to the minimum rate of energy that you have while you are not doing anything - while at rest. There are a couple of important criteria that you have to meet in order to measure this rate properly, such as complete undisturbed state, thermally neutral environment, etc.