RMR (resting metabolic rate)
RMR is energy expenditure at rest but under less strict conditions than BMR — you have not necessarily fasted overnight or lain still in a dark room. It usually reads slightly higher than BMR, and the two terms are frequently used interchangeably even though they are not identical.
Example
Most online "BMR calculators", including this site's, use the Mifflin-St Jeor equation, which was fitted to resting rather than strictly basal measurements.