Topic and comment in the context of "Grammatical theory"

An outline, also called a hierarchical outline, is a list arranged to show hierarchical relationships and is a type of tree structure. An outline is used to present the main points (in sentences) or topics (terms) of a given subject. Each item in an outline may be divided into additional sub-items. If an organizational level in an outline is to be sub-divided, it shall have at least two subcategories, although one subcategory is acceptable on the third and fourth levels, as advised by major style manuals in current use. An outline may be used as a drafting tool of a document, or as a summary of the content of a document or of the knowledge in an entire field. It is not to be confused with the general context of the term "outline", which is a summary or overview of a subject presented verbally or written in prose (for example, The Outline of History is not an outline of the type presented below). The outlines described in this article are lists, and come in several varieties.

A sentence outline is a tool for composing a document, such as an essay, a paper, a book, or even an encyclopedia. It is a list used to organize the facts or points to be covered, and their order of presentation, by section. Topic outlines list the subtopics of a subject, arranged in levels, and while they can be used to plan a composition, they are most often used as a summary, such as in the form of a table of contents or the topic list in a college course's syllabus.

In linguistics, an object is any of several types of arguments. In subject-prominent, nominative-accusative languages such as English, a transitive verb typically distinguishes between its subject and any of its objects, which can include but are not limited to direct objects, indirect objects, and arguments of adpositions (prepositions or postpositions); the latter are more accurately termed oblique arguments, thus including other arguments not covered by core grammatical roles, such as those governed by case morphology (as in languages such as Latin) or relational nouns (as is typical for members of the Mesoamerican Linguistic Area).In ergative-absolutive languages, for example most Australian Aboriginal languages, the term "subject" is ambiguous, and thus the term "agent" is often used instead to contrast with "object", such that basic word order is described as agent–object–verb (AOV) instead of subject–object–verb (SOV). Topic-prominent languages, such as Mandarin, focus their grammars less on the subject-object or agent-object dichotomies but rather on the pragmatic dichotomy of topic and comment.

In linguistics, a grammatical agent is the thematic relation of the cause or initiator to an event. The agent is a semantic concept distinct from the subject of a sentence as well as from the topic. While the subject is determined syntactically, primarily through word order, the agent is determined through its relationship to the action expressed by the verb. For example, in the sentence "The little girl was bitten by the dog", girl is the subject, but dog is the agent.

The word agent comes from the present participle agens, agentis ('the one doing') of the Latin verb agere, to 'do' or 'make'.