The crossword solution for the term 'ION, AT TIMES' is 'ATOM'. An ATOM is the smallest unit of matter that can exist and is composed of a nucleus surrounded by electrons. Atoms are the building blocks of all matter and are made up of protons, neutrons, and electrons. Ions are atoms that have gained or lost electrons, resulting in a net positive or negative charge. At times, an ATOM can become an ion due to the gain or loss of electrons.