criticaladj/ˈkɹɪt.ɪ.kəl/

• 1

  Inclined to find fault or criticize.

  • A good teacher is fair but critical.
  • Let us go back to the beginning and consider what the charge is that has made people so critical of me, and has encouraged Meletus to draw up this indictment.
• 2

  Pertaining to, or indicating, a crisis or turning point.

  • This is a critical moment.
  • Such a scandal as the prosecution of a brother for forgery—with a verdict of guilty—is a most truly horrible, deplorable, fatal thing. It takes the respectability out of a family perhaps at a critical moment, when the family is just assuming the robes of respectability: […] it is a black spot which all the soaps ever advertised could never wash off.
• 3

  Extremely important.

  • It's critical that you deliver this on time.
  • Oxygen levels on Earth skyrocketed 2.4 billion years ago, when cyanobacteria evolved photosynthesis:[…]. The evolutionary precursor of photosynthesis is still under debate, and a new study sheds light. The critical component of the photosynthetic system is the “water-oxidizing complex”, made up of manganese atoms and a calcium atom.
• 4

  Relating to criticism or careful analysis, such as literary or film criticism.

  • The movie was a critical success, but bombed at the box-office.
  • “Unless you are purchasing cereal from a health food store, many brands that are marketed as healthy are usually full of sugar and processed ingredients,” says Garcia. So when you’re choosing cereal, bread or any other whole-grain product, Garcia recommends reading labels with a critical eye.
• 5

  human-scienceslinguisticssciencesRelating to criticism or careful analysis, such as literary or film criticism.

• 6

  medicinesciencesOf a patient condition involving unstable vital signs and a prognosis that predicts the condition could worsen; or, a patient condition that requires urgent treatment in an intensive care or critical care medical facility.

  • The patient's condition is critical.
• 7

  medicinesciencesIn such a condition.

  • The patient is critical.
  • Two critical after fatal Wimbledon school crash
• 8

  Likely to go out of control if disturbed, that is, opposite of stable.

  • The political situation was so critical that the government declared the state of siege.

criticalnoun/ˈkɹɪt.ɪ.kəl/

• 1

  A critical value, factor, etc.

  • The second undamped system criticals show a greater percentage depression than the first.
  • Finally, criticals are high-risk, high-value items that give the final product a competitive advantage in the marketplace […] Criticals, in part, determine the customer's ultimate cost of using the finished product — in our example, the computer.
• 2

  critical hit

• 3

  In breakdancing, a kind of airflare move in which the dancer hops from one hand to the other.