"current, contemporary, now in existence," 1870, from present (adj.) + day.
Entries linking to present-day
present adj.
c. 1300, "being in the same place as someone or something;" early 14c., "existing at the time," from Old French present "evident, at hand, within reach;" as a noun, "the present time" (11c., Modern French présent) and directly from Latin praesentem (nominative praesens) "present, at hand, in sight; immediate; prompt, instant; contemporary," from present participle of præesse "be before (someone or something), be at hand," from prae- "before" (see pre-) + esse "to be" (from PIE root *es- "to be").
Meaning "abiding in a specified place" is from mid-14c. in English. As a grammatical tense expressing action or being in the present time, recorded from late 14c.
day n.
Old English dæg "period during which the sun is above the horizon," also "lifetime, definite time of existence," from Proto-Germanic *dages- "day" (source also of Old Saxon, Middle Dutch, Dutch dag, Old Frisian di, dei, Old High German tag, German Tag, Old Norse dagr, Gothic dags), according to Watkins, from PIE root *agh- "a day." He adds that the Germanic initial d- is "of obscure origin." But Boutkan says it is from PIE root *dhegh- "to burn" (see fever). Not considered to be related to Latin dies (which is from PIE root *dyeu- "to shine").
Meaning originally, in English, "the daylight hours;" it expanded to mean "the 24-hour period" in late Anglo-Saxon times. The day formerly began at sunset, hence Old English Wodnesniht was what we would call "Tuesday night." Names of the weekdays were not regularly capitalized in English until 17c.
From late 12c. as "a time period as distinguished from other time periods." Day-by-day "daily" is from late 14c.; all day "all the time" is from late 14c. Day off "day away from work" is attested from 1883; day-tripper first recorded 1897. The days in nowadays, etc. is a relic of the Old English and Middle English use of the adverbial genitive.
All in a day's work "something unusual taken as routine" is by 1820. The nostalgic those were the days is attested by 1907. That'll be the day, expressing mild doubt following some boast or claim, is by 1941. To call it a day "stop working" is by 1919; earlier call it a half-day (1838). One of these days "at some day in the near future" is from late 15c. One of those days "a day of misfortune" is by 1936.