What does it means? Plasma: Particles are in ionized condition.
Usually, atom contains an equal number of positive and negative charges; the positive charges in the nucleus are surrounded by an equal number of negatively charged electrons, and each atom is electrically "neutral."
By the addition of heat or other energy causes a significant number of atoms to release some or all of their electrons. The remaining parts of those atoms are left with a positive charge, and the detached negative electrons which are free to move about. Those atoms and the resulting electrically charged electrons are said to be "ionized." When enough atoms are ionized to significantly affect the electrical characteristics then they are said to be in plasma state. This plasma state is found in stars, common in universe.