Subject (grammar)
= Subject
{disambiguate=grammar}
A <subject (grammar)> is a grammatical relation identified through language-specific structural tests, such as <word order> and <grammatical agreement>. It often corresponds to the actor in a simple active <clause (grammar)>, but that semantic association is not its definition. A <noun phrase> can be a <subject (grammar)> without describing an intentional action.<Universal Dependencies annotation guidelines>[nsubj, Definition, grammatical tests and passive subjects]{ref}
Compare `A gust broke the branch` and `The branch was broken by a gust`. The first has `a gust` as its <subject (grammar)>; in the <passive voice> version, `the branch` has that relation. The participants' involvement in the event has not simply exchanged places. Separating grammatical relations from <thematic roles> explains the contrast.
In <Universal Dependencies>, a nominal passive subject can receive `nsubj:pass`, explicitly preserving its subject status. Such a representation supports a testable structural account and prevents a procedure from assigning “subject” solely to whichever expression appears to name a doer.