| NEUTRON | One of the types of subatomic particle at the centre of an atom (7) |
| ION | Particle at the centre of espionage (3) |
| HADRON | Type of subatomic particle made up of quarks |
| MESON | Type of subatomic particle |
| SALTEM | A restrictive particle, at least, anyhow |
| ELEMENTARY | Simple description of subatomic particle |
| RADIATION | Dangerous particles at a nuclear power station, perhaps (9) |
| SYNONYM | Any one of the types of words listed in a thesaurus (7) |
| RHIZOME | One of the types of subterranean botanical structures along with bulbs, corms, rootstocks and tubers |
| NUCLEUS | In physics, the positively charged dense region at the centre of an atom (7) |
| FEYNMAN | Pictorial representations of the mathematical expressions describing the behavior of subatomic particles (7,7) |
| DIAGRAM | Pictorial representations of the mathematical expressions describing the behavior of subatomic particles (7,7) |
| EXTREME | ___ fighting, a combat sport with no regulation of the types of blow allowed (7) |
| NUCLEON | Part of the centre of an atom (7) |
| NUCLEAR | Relating to the centre of an atom (7) |
| INBOARD | Popular group of executives towards the centre of an aircraft? (7) |
| FRUIT | General word for one of the types of food grown by French gardener La Quintinie at Le Potager du Roi for the table of the Sun King, Louis XIV (5) |
| GREYMATTER | Serving to process information in the brain, one of the types of tissue forming part of the central |
| IRONIES | Examples of the type of humour that is found in clubs? (7) |
| ABBEY | One of the types of buildings that were disbanded during Henry VIII's Dissolution of the Monasteries (5) |
