[e-spree duh kawr] 
| a sense of unity and of common interests and responsibilities, as developed among a group of persons closely associated in a task, cause, enterprise, etc. |
| esprit de corps (də kôr') n. A common spirit of comradeship, enthusiasm, and devotion to a cause among the members of a group. See Synonyms at morale. [French : esprit, spirit + de, of + corps, group, body.] |
The feeling of camaraderie among members of a group or an organization: “The campers have been together for only one week, but they are already bound by a strong esprit de corps.” From French, meaning “group spirit.”