Live Hand
A live hand is a hand that is still eligible to win the pot. It has the correct number of cards and has not been mucked or ruled dead.
The simple explanation
If you have not folded and your cards are valid, your hand is live. A folded or mucked hand is dead.
A closer look
A hand can become dead if it touches the muck, has the wrong number of cards, or if the player acts out of turn in some cases. Protect your cards to keep them live. At showdown, a live hand must be shown to win.
A practical example
A player has not folded and holds two cards in front of him. His hand is live.
Full explanation
A live hand is a hand that is still eligible to win the pot. It has the correct number of cards and has not been mucked or ruled dead.
A live hand can still win the pot.
A mucked hand is dead.
Protect your cards.
Show it at showdown to win.