Description of the card from http://www.aeclectic.net/tarot/basics/death.shtml :

Basic Meaning
"Yes, the Death card can signal a death in the right circumstances (a question about a very sick or old relative, for example), but unlike its dramatic presentation in the movies, the Death card is far more likely to signal transformation, passage, change. Scorpio, the sign of this card, has three forms: scorpion, serpent, eagle. The Death card indicates this transition from lower to higher to highest. This is a card of humility, and it may indicate the Querent as being brought low, but only so that they can then go higher than they ever have before. Wang notes that Death "humbles" all, but it also "exults." Always keep in mind that on this card of darkness there is featured a sunrise as well."

The Death tarot card is the trump card of the Tarot deck.