| 11223 | Definitions usually have a term, a 'definiendum' containing the term, and a defining 'definiens' |
| 11215 | Notable definitions have been of piety (Plato), God (Anselm), number (Frege), and truth (Tarski) |
| 11225 | A definition needs to apply to the same object across possible worlds |
| 11227 | The 'revision theory' says that definitions are rules for improving output |
| 11221 | A definition can be 'extensionally', 'intensionally' or 'sense' adequate |
| 11224 | Traditional definitions are general identities, which are sentential and reductive |
| 11226 | Traditional definitions need: same category, mention of the term, and conservativeness and eliminability |
| 11217 | Chemists aim at real definition of things; lexicographers aim at nominal definition of usage |
| 11216 | If definitions aim at different ideals, then defining essence is not a unitary activity |
| 11218 | Stipulative definition assigns meaning to a term, ignoring prior meanings |
| 11220 | Ostensive definitions look simple, but are complex and barely explicable |
| 14965 | Truth rests on Elimination ('A' is true → A) and Introduction (A → 'A' is true) |
| 14968 | A weakened classical language can contain its own truth predicate |
| 11222 | The ordered pair <x,y> is defined as the set {{x},{x,y}}, capturing function, not meaning |
| 14964 | The Liar reappears, even if one insists on propositions instead of sentences |
| 14969 | Strengthened Liar: either this sentence is neither-true-nor-false, or it is not true |