atom
noun [ C ] uk/ˈæt.əm/ us/ˈæt̬.əm/
B2 原子
the smallest unit of any chemical element, consisting of a positive nucleus surrounded by negative electrons. Atoms can combine to form a molecule
A molecule of carbon dioxide (CO2) has one carbon atom and two oxygen atoms. 二氧化碳（CO2）分子是由一个碳原子和两个氧原子构成的。
figurative He hasn't an atom of sense (= he has no sense), that boy. 那个孩子啊，一点头脑也没有。
- More examples
- The nucleus of a deuterium atom contains a proton and a neutron.
- Scientists are working to harness the power of the atom.