 Subordinate clause

A subordinate clause is a clause embedded within a larger grammatical construction, where it supplies part of the structure or interpretation. It contrasts with a main clause in that construction. Subordination describes a relationship among units, rather than merely identifying whichever words occur after a comma.^[ref]

In the original example The sensor stopped because the battery failed, because the battery failed supplies a reason for the main assertion. In I know that the sensor stopped, the embedded material instead supplies what is known. Both contain their own subject-predicate organization, while contributing differently to the larger expression.

A structural analysis can vary the embedded content while preserving its role in the surrounding syntax. Comparing that pattern across examples helps distinguish an embedded grammatical constituent from an unrelated second assertion. The analysis must also keep the grammatical embedding separate from whether the speaker actually believes the embedded content.