urgence

In a sentence

• J'ai appelé le médecin en urgence.

  I called the doctor urgently.

  Here, 'urgence' is used as an adverbial phrase ('en urgence'), meaning 'urgently' or 'without delay', modifying the action of calling.

• L'hôpital a une salle spéciale pour les urgences.

  The hospital has a special room for emergencies.

  In this case, 'urgences' is used as a noun to refer to medical emergencies, specifically the area designed for urgent medical situations in a hospital.

• Il est important de savoir quoi faire en cas d'urgence.

  It's important to know what to do in case of an emergency.

  Here, 'urgence' is a noun again, but referring generally to any kind of urgent or critical situation.