For an open system, there is a wall that allows penetration by matter.

At school, all students are taught in all three official languages, although divided by age group and subject matter.

He marveled at the wonders of the human brain and soul, because even when distorted by dark matter, they were giving him an important message.

Then they arranged their books on the shelves by subject matter.

A hierarchical arrangement of class titles organized into four main groups by related subject matter.

That theory describes gravity as the bending of space-time by matter and energy.

List of successful agrégés by subject matter and year from 1809 to 1950 (French)

Food products were also found contaminated by radioactive matter in several places in Japan.

Trapped, suffocating, surrounded by enemies-no matter that they had meant her well.

It allows the user to browse through the catalog by country, language or subject matter.