This is the 9149th most frequent Japanese word.
煉瓦
Brick.
'煉瓦' is used here as a material for construction.
この家は煉瓦で建てられています。
This house is built with bricks.
'煉瓦' is used metaphorically to describe hardness.
彼は煉瓦のように硬い心を持っています。
He has a heart as hard as a brick.
'煉瓦' specifies the appearance and material of the wall.