Yesterday is a temporal construct of the relative

past The past is the set of all Spacetime#Definitions, events that occurred before a given point in time. The past is contrasted with and defined by the present and the future. The concept of the past is derived from the linear fashion in which human ...

; literally of the

day A day is the time rotation period, period of a full Earth's rotation, rotation of the Earth with respect to the Sun. On average, this is 24 hours (86,400 seconds). As a day passes at a given location it experiences morning, afternoon, evening, ...

before the current day (today), or figuratively of earlier periods or times, often but not always within living memory.

Learning and language

The concepts of "yesterday", " today" and " tomorrow" are among the first relative time concepts acquired by

infant In common terminology, a baby is the very young offspring of adult human beings, while infant (from the Latin word ''infans'', meaning 'baby' or 'child') is a formal or specialised synonym. The terms may also be used to refer to juveniles of ...

s. In language a distinctive noun or

adverb An adverb is a word or an expression that generally modifies a verb, an adjective, another adverb, a determiner, a clause, a preposition, or a sentence. Adverbs typically express manner, place, time, frequency, degree, or level of certainty by ...

for "yesterday" is present in most but not all languages, though languages with ambiguity in vocabulary also have other ways to distinguish the immediate past and immediate future. "Yesterday" is also a relative term and concept in

grammar In linguistics, grammar is the set of rules for how a natural language is structured, as demonstrated by its speakers or writers. Grammar rules may concern the use of clauses, phrases, and words. The term may also refer to the study of such rul ...

and

syntax In linguistics, syntax ( ) is the study of how words and morphemes combine to form larger units such as phrases and sentences. Central concerns of syntax include word order, grammatical relations, hierarchical sentence structure (constituenc ...

.The Function of tense in texts Jadranka Gvozdanović, Theodorus Albertus Johannes Maria Janssen, Östen Dahl - 1991 - Volumes 144 to 146 - Page 100 "Yesterday is relative to the day 'where we are', a minute ago to the minute, more or less, 500 years ago to 'our present' in a thematically suitable sense, perhaps 'this century', or 'modern times'. " Yesterday is an abstract concept in the sense that events that occurred in the past do not exist in the present reality, though their consequences persist. Some languages have a hesternal tense: a dedicated grammatical form for events of the previous day.

References

{{Time topics Past Days