| atom |
the smallest possible unit of a chemical element. The major parts of atoms contain protons, neutrons, and electrons. They are the basis of all matter in the universe. [2 definitions] |
| atomic |
having to do with atoms or energy made from atoms. [2 definitions] |
| atomic bomb |
a very destructive bomb; atom bomb. Its power comes from the great amount of energy released when atoms are split. |
| atomic energy |
the energy that is released by atoms in nuclear reactions. [2 definitions] |
| at once |
at the same time. [2 definitions] |
| atone |
to make up for; make amends. |
| at one's heels |
following closely. |
| atop |
at or on the highest point of. |
| at present |
right now. |
| at rest |
not active, not moving, or sleeping. |
| a trifle |
a little bit; somewhat; slightly. |
| atrium |
a courtyard inside a building, either open to the sky or with a glass ceiling. [2 definitions] |
| atrocious |
very evil, cruel, or brutal. [2 definitions] |
| at sea |
on the ocean waters. [2 definitions] |
| at stake |
in danger of being lost. |
| attach |
to join, fasten, or connect. [3 definitions] |
| attached |
feeling strong affection for and not wanting to part with. |
| attachment |
the act or process of attaching. [3 definitions] |
| attack |
to begin to cause harm to. [5 definitions] |
| attain |
to gain or achieve through work. [2 definitions] |
| attempt |
to try or seek. [3 definitions] |