Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Medical
  • Scrabble
  • Spanish Central
  • Learner's Dictionary


noun plas·ma \ˈplaz-mə\

Simple Definition of plasma

  • medical : the watery part of blood that contains blood cells

  • : a substance that is similar to a gas but that can carry electricity

  • : a type of visual display for computers, televisions, etc., that uses plasma with electrical charges between two sheets of glass and that produces pictures that are very clear and bright

Full Definition of plasma

  1. 1 :  a green faintly translucent quartz

  2. 2 [New Latin, from Late Latin] a :  the fluid part of blood, lymph, or milk as distinguished from suspended material; especially :  blood plasma b :  the juice that can be expressed from muscle

  3. 3 :  protoplasm

  4. 4 :  a collection of charged particles (as in the atmospheres of stars or in a metal) containing about equal numbers of positive ions and electrons and exhibiting some properties of a gas but differing from a gas in being a good conductor of electricity and in being affected by a magnetic field

  5. 5 :  a display (as a television screen) consisting of discrete cells of plasma sandwiched between two layers of glass and electrodes such that each cell emits light when it receives an electric current

plas·mat·ic play \plaz-ˈma-tik\ adjective

Examples of plasma

  1. the plasma that makes up a star

  2. Our new TV is a 50-inch plasma.

Origin of plasma

German, from Late Latin, something molded, from Greek, from plassein to mold — more at plaster

First Known Use: 1517

Rhymes with plasma

Medical Dictionary


noun plas·ma \ˈplaz-mə\

Medical Definition of plasma

  1. 1a:  the fluid part especially of blood, lymph, or milk that is distinguished from suspended material—see blood plasmab:  the juice that can be expressed from muscle

  2. 2:  protoplasm

  3. 3:  a mixture of starch and gel used as an ointment base

Seen and Heard

What made you want to look up plasma? Please tell us where you read or heard it (including the quote, if possible).


February 12, 2016

of, relating to, or suggestive of marble

Get Word of the Day daily email!


Take a 3-minute break and test your skills!


How much does a batman (the Turkish unit of measurement) weigh?

100 pounds 196.5 pounds 2.2 pounds 16.96 pounds
Name That Thing

10 quick questions: hear them, spell them, and see how your skills compare to the crowd.


Test Your Knowledge - and learn some interesting things along the way.