sync up

• synch up

sync up (third-person singular simple present syncs up, present participle syncing up or synching up, simple past and past participle synced up or synched up)

1. (ambitransitive, of two or more events, informal) To synchronize.

   Many people believe in menstrual synchrony, the idea that women's menstrual periods sometimes sync up when they work closely together, but the scientific methodology for confirming its existence remains weaker than many assume.

   They asked us to sync up our proposed conference dates and submit our answer by next Tuesday.

   • 2026 February 16, Alicia Eler, “Lunar New Year, Ramadan and Lent in rare alignment this year. The holidays follow different solar and lunar calendars, but some of them sync up in 2026”, in Minnesota Star Tribune‎^[1], archived from the original on 16 February 2026:

     This Tuesday and Wednesday, four holidays from different cultures and religions overlap in a rare calendar year. The celebrations of Fat Tuesday (Mardi Gras) and Lunar New Year both occur on Tuesday, Feb. 17 [2026]. This won't happen again until Feb. 13, 2029, according to the websites chinahighlights.com and mardigrasneworleans.com. Ramadan is expected to start Tuesday evening, pending official confirmation, and Lent ([which begins on] Ash Wednesday) begins on Feb. 18. Last year, Ramadan and Lent began within a week of each other on Feb. 28 and March 5. The holidays are all happening within two days this year because several long solar, lunar and lunisolar calendar cycles sync up. Lunar New Year happens on the second new moon after winter solstice, which is also Fat Tuesday (Mardi Gras) — 47 days before Easter Sunday.

   1. (television, transitive) To synchronize (footage) so that the audio and video components play together in correct alignment.

      You could tell that the video and the audio hadn't been synced up properly, so watching the movie was kind of annoying.

• sunk up is sometimes encountered as a past participle, by confusion with sink.