log into

Blend of log in (where in is an adverb, not a preposition) + into.

log into (third-person singular simple present logs into, present participle logging into, simple past and past participle logged into)

1. (transitive, sometimes proscribed) To log in (“gain access, usually by providing a previously registered username and password”) to (a computer system).

   Synonym: log onto

   • 2006, Mark Pilgrim, “ Animate Wikipedia History”, in Greasemonkey Hacks: Tips & Tools for Remixing the Web with Firefox, Sebastopol, Calif.: O’Reilly Media, Inc., →ISBN, page 433:

     You can include metadata such as the revision date, the author (if the person who made the change had logged into Wikipedia), and the summary the author entered when he made the revision.

   • 2006 September 5, Seth Schiesel, “Online Game, Made in U.S., Seizes the Globe”, in The New York Times‎, New York, N.Y.: The New York Times Company, →ISSN, →OCLC, archived from the original on 2013-06-15:

     Less than two years after its introduction, World of Warcraft, made by Blizzard Entertainment, based in Irvine, Calif., is on pace to generate more than $1 billion in revenue this year with almost seven million paying subscribers, who can log into the game and interact with other players.

   • 2020, Katlyn Duncan, Barefoot on the Beach, London: HQ, HarperCollinsPublishers Ltd, →ISBN, page 44:

     A bra hung from the side of her computer monitor, and Renee delicately tossed it on the bed before logging into the desktop.

   • 2021 September 28, Lee Mandelo, chapter 20, in Summer Sons, New York, N.Y.: Tordotcom, →ISBN, page 230:

     Riley handed over his phone, which was logged into the university’s library database and open to an article.

2. Used other than figuratively or idiomatically: see log,‎ into: (ditransitive) to log (“enter, record, input”) (someone or something) into (somewhere).
   • 1980, Ann Rule, chapter 30, in The Stranger Beside Me, New York, N.Y.: W. W. Norton & Company, →ISBN, page 245:

     There was a lot of evidence; it would one day take eight hours to log it into the trial, and, yet, there was so little that could help in the probe as far as leading the investigators to the man they sought.

   • 2002 November, Andrew Swaffer, Katrina O’Brien, Darroch Donald, “Sydney: Directory”, in Australia Handbook, Bath, Somerset: Footprint Handbooks Ltd, →ISBN, page 122:

     Log your name into the computer to see if any mail awaits.

   • 2004, Michael Dregni, “Notes”, in Django: The Life and Music of a Gypsy Legend, Oxford, Oxfordshire: Oxford University Press, →ISBN, page 283:

     Django was logged into the Hôpital Lariboisière as “Jean Reinloardt,” age 18.

• “log on, v.”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present: “often used with to […] often written as log onto and log into”
• “"log in to" or "log into" or "login to"”, in English Language & Usage, Stack Exchange, 2010–present.
• Dara Becker (2018) “‘Login to’ or ‘log in to’ or ‘log into’? Are you guessing and hoping it’s right?”, in LinkedIn‎, archived from the original on 2024-03-16: “We should not combine a verb particle and a preposition into one word. Log into is incorrect.”
• Catherine Traffis (2020) “Into or In To—How Do I Use Them?”, in Grammarly‎, archived from the original on 2020-03-12:

  A common error is to confuse into, spelled as one word, with the two words in to. […] In the early days of radio, a common error was to write about tuning into a favorite station. Today, in cyberspace, the most common misstep is to write about logging into a program, operating system, app, or website.

• Candace Osmond (2023) “Log On or Log In – What’s the Difference?”, in Grammarist‎, archived from the original on 2023-09-27: “If you’re using the term “log in” as a verb, it should be followed by the word “to,” as in “Please log in to your account.” The term “log into” is more informal but can be used in instances like texting or something. It’s not technically correct, but I’ve seen it thrown around.”