attrition

Grinding down or wearing away by friction.

A gradual reduction in number.

A gradual, natural reduction in membership or personnel, as through injury, incapacitation, retirement, resignation, or death.

The loss of participants during an experiment.

The loss of a first or second language or a portion of that language.

The wearing of teeth due to their grinding.

Imperfect contrition or remorse.

To grind or wear down through friction.

To reduce the number of (jobs or workers) by not hiring new employees to fill positions that become vacant (often with out).

To undergo a reduction in number.