Noun
1. the act of sharing in the activities of a group;
"the teacher tried to increase his students' engagement in class activities"2. a connection of inclusion or containment;
"he escaped involvement in the accident""there was additional involvement of the liver and spleen"3. a sense of concern with and curiosity about someone or something;
"an interest in music"4. a usually secretive or illicit sexual relationship
5. the condition of sharing in common with others (as fellows or partners etc.)