Killmail
A killmail is created whenever a ship or structure is destroyed. All participants in the kill are listed with the damage they did, along with the victim's ship, fittings, and cargo. Any modules or cargo that were dropped are specified. Only the person contributing the final blow, and the victim, get the killmail.
Since late 2007 killmails are found in the Character Sheet/Combat Log. Killmails from before that date were sent as Eve-mails, which is why this term came into existence.
Most Corporations and Alliances post their killmails to a killboard.
The details of the current killmail system are described in this dev blog.
Example Killmail
2009.01.10 00:00:00
Victim: A Victim
Corp: A Corp
Alliance: An Alliance
Faction: NONE
Destroyed: Kestrel
System: Jita
Security: 0.9
Damage Taken: 974
Involved parties:
Name: A Killer (laid the final blow)
Security: 3.0
Corp: Killer Corp
Alliance: Killer Alliance
Faction: NONE
Ship: Ishtar
Weapon: Heavy Electron Blaster II
Damage Done: 974
Destroyed items:
Cynosaural Field Generator I
Veldspar 1
Dropped items:
Warp Scrambler II