Full Idea
Situation semantics is a variation of the truth-conditional approach, taking the salient unit of analysis not to be the possible world, or some complete consistent index, but rather the more modest 'situation'.
Gist of Idea
We can rest truth-conditions on situations, rather than on possible worlds
Source
JC Beall / G Restall (Logical Pluralism [2006], 5.5.4)
Book Reference
Beall,J/Restall,G: 'Logical Pluralism' [OUP 2006], p.58
A Reaction
When I read Davidson (and implicitly Frege) this is what I always assumed was meant. The idea that worlds are meant has crept in to give truth conditions for modal statements. Hence situation semantics must cover modality.