- pressed tightly together; driven firmly in; wedged in; esp., firmly lodged in the jaw: said of a tooth unable to erupt properly because of its abnormal position, lack of space, etc.
- financially or otherwise strained by heavy demand on public services, as schools: said esp. of areas having a high population density or a large proportion of federal employees living on nontaxable federal property such as a military base
- Wedged together at the broken ends. Used of a fractured bone.
- Placed in the alveolus in a manner prohibiting eruption into a normal position. Used of a tooth.
- Wedged or packed in, so as to fill or block an organ or a passage: impacted feces.
- simple past tense and past participle of impact