| SC | Zsyntax.Labelled.Rule.Interface, Zsyntax.Labelled.Rule | 
| SchemaLCtxt | Zsyntax.Labelled.Rule.Interface, Zsyntax.Labelled.Rule | 
| search |   | 
| 1 (Function) | Otter.Internal.Search, Otter | 
| 2 (Function) | Zsyntax | 
| searchLabelled | Zsyntax | 
| SearchNode | Otter.Internal.Structures | 
| SearchProperRule | Otter.Internal.Structures | 
| SearchRes | Otter.SearchRes, Otter, Zsyntax | 
| SearchRule | Otter.Internal.Structures | 
| Sequent | Zsyntax.Formula, Zsyntax | 
| SLC | Zsyntax.Labelled.Rule.Interface, Zsyntax.Labelled.Rule | 
| SpaceTooBig | Otter.SearchRes, Otter, Zsyntax | 
| SQ | Zsyntax.Formula, Zsyntax | 
| SSchema | Zsyntax.Labelled.Rule.Interface, Zsyntax.Labelled.Rule | 
| SSEmptyGoal | Zsyntax.Labelled.Rule.Interface, Zsyntax.Labelled.Rule | 
| SSFullGoal | Zsyntax.Labelled.Rule.Interface, Zsyntax.Labelled.Rule | 
| Stage | Otter.Internal.Structures | 
| SubCtxt | Zsyntax.Labelled.Rule.Interface, Zsyntax.Labelled.Rule | 
| subCtxtOf | Zsyntax.Labelled.Rule.Interface, Zsyntax.Labelled.Rule | 
| Subsumable | Otter.Internal.Structures, Otter | 
| subsumes | Otter.Internal.Structures, Otter | 
| SupersetClosed | Zsyntax.ReactionList | 
| switchN | Zsyntax.Labelled.Rule.Interface, Zsyntax.Labelled.Rule |