1. A situation in which one object is hit by another one: During their game outside on the lawn, the two boys hurt themselves by colliding together, an act of impaction!
2. A bodily disorder in which the faces are wedged tightly in the lower colon: After a postmortem was done, the specialist diagnosed the horse to have had an impaction, or a solid immobile bulk of stool, due to dehydration and colitis in the stomach.
3.The condition of being pressed firmly or tightly together: The impaction of earwax, or cerumen, against the eardrum caused tinnitus in Adam's ears.
4. A situation of a tooth being crowded in its socket and which cannot erupt in a normal way: When Martin went to the dentist's for a regular checkup, his dentist diagnosed an impaction in Martin's upper row of teeth and told him that it had to be taken care of right away.