stone

In a sentence

• La pierre est un matériau de construction très solide.

  The stone is a very sturdy building material.

  Here, 'stone' refers to its inherent physical qualities and usage in construction.

• J'ai trouvé une belle pierre au bord de la rivière.

  I found a beautiful stone by the river's edge.

  In this sentence, 'stone' denotes a small rock or pebble, indicating an object found in nature.

• Son cœur était aussi dur qu'une pierre.

  Her heart was as hard as a stone.

  Here, 'stone' is used metaphorically to describe the hardness or lack of emotion in someone's heart.