A concessive clause is a °clause that expresses a °concessive circumstance of the °event described by the °matrix clause.
concessive relation (SEM) / construction (CXN) = a relation between two events such that there is an expected causal relation between the two events, but the opposite of the sec- ond event, expressed in the apodosis, unexpectedly occurs. Example: Although it was raining, I went out is an instance of a concessive relation and construction: the expected causal relation is that rain would lead to my staying in; but in fact I went out. The speaker has a positive epistemic stance toward the concessive construction. A concessive may express a content, epistemic, or speech act causal relation. (Section 17.3.2)