Mura

The Japanese word that is translated into English as unevenness, variation, non-uniformity or irregularity.  It can occur when there is an uneven number of customer orders by seasons, the day of the week, or the week within the month. It also occurs when workers are unable to help out or support others when demand shifts, because they have not received the proper training. Internal processes can create mura when the work is completed in batches, such as at the end of the day or week, which creates a pile of work (bottleneck) for the next person in the process.

It is one of three barriers to an efficient use of resources within TPS (muda, mura and muri).