al·tru·ism 
(ăltr-ĭz′əm)
(ăltr-ĭz′əm)n.
1. Unselfish concern for the welfare of others; selflessness.
2. Zoology Instinctive behavior that is detrimental to the individual but favors the survival or spread of that individual's genes, as by benefiting its relatives.
[French altruisme, probably from Italian altrui, someone else, from Latin alter, other; see al-1 in the Appendix of Indo-European roots.]
altru·ist n.
al′tru·istic adj.
al′tru·isti·cal·ly adv.