| ORATIONS | Discourses on the zero quotas |
| REYNOLDS | First president of the Royal ' Academy and leading portraitist of his day who set out his theories on art in a series of 15 lectures published in Discourses on Art (8) |
| OPER | Letters on the zero button |
| DESCARTES | Rene ---, 17th Century French philosopher and mathematician who wrote Discourse On The Method (9) |
| ECO | Italian medievalist, semiotician and writer who penned the discourse on aesthetics On Beauty and several novels including Foucault's Pendulum and the international bestseller titled The Name of the Ro |
| NOUGHT | After the point, should come the zero (6) |
| RATIONS | The animal treated is on restricted food quotas (7) |
| AMPLITUDE | In physics, the maximum displacement from the zero or mean position of a periodic motion or curve |
| THEORISE | Speculate about the zero improvement |
| MITSUBISHI | Japanese company that made the Zero fighter aircraft (10) |
| THEORISES | Thinks up possible reasons for the zero increments? (9) |
| SUM | The zero-___ theory |
| ONE | Any number raised to the zero power |
| LEAVES | "Eats, Shoots & ___: The Zero Tolerance Approach to Punctuation" |
| NOERRORS | The "0" in "4 5 0," on a scoreboard |
| EVELYN | Arboriculturist and bibliophile who wrote the discourse on trees Sylva, an early work on air pollution Fumifugium and a diary that rivalled that of his friend Samuel Pepys (6) |
| COMPLEATANGLER | The ___, discourse on fishing by Izaak Walton (8,6) |
| QOM | Pilgrimage centre instigating quotas on Mecca |
| LORETTA | Ms. Lynn whose first big hit "I'm a Honky Tonk Girl" was recorded under the Zero Records label of Vancouver |
| ORIGIN | The zero I ring is wrong, for a start (6) |
