linguistic:voice_change, information:classification, structural:summarization, stylistic:style_transfer, structural:reformatting
Uses of the term

In modern linguistic theory, tense is understood as a category that expresses (grammaticalizes) time reference; namely one which, using grammatical means, places a state or action in time. Nonetheless, in many descriptions of languages, particularly in traditional European grammar, the term "tense" is applied to verb forms or constructions that express not merely position in time, but also additional properties of the state or action – particularly aspectual or modal properties.

The category of aspect expresses how a state or action relates to time – whether it is seen as a complete event, an ongoing or repeated situation, etc. Many languages make a distinction between perfective aspect (denoting complete events) and imperfective aspect (denoting ongoing or repeated situations); some also have other aspects, such as a perfect aspect, denoting a state following a prior event. Some of the traditional "tenses" express time reference together with aspectual information. In Latin and French, for example, the imperfect denotes past time in combination with imperfective aspect, while other verb forms (the Latin perfect, and the French passé composé or passé simple) are used for past time reference with perfective aspect.

The category of mood is used to express modality, which includes such properties as uncertainty, evidentiality, and obligation. Commonly encountered moods include the indicative, subjunctive, and conditional. Mood can be bound up with tense, aspect, or both, in particular verb forms. Hence, certain languages are sometimes analysed as having a single tense–aspect–mood (TAM) system, without separate manifestation of the three categories.

The term tense, then, particularly in less formal contexts, is sometimes used to denote any combination of tense proper, aspect, and mood. As regards English, there are many verb forms and constructions which combine time reference with continuous and/or perfect aspect, and with indicative, subjunctive or conditional mood. Particularly in some English language teaching materials, some or all of these forms can be referred to simply as tenses (see below).

Particular tense forms need not always carry their basic time-referential meaning in every case. For instance, the historical present is a use of the present tense to refer to past events. The phenomenon of fake tense is common crosslinguistically as a means of marking counterfactuality in conditionals and wishes.