A temporal crack, or "crack in time", was often a descriptive phrase for temporal phenomenon.
The Fourth Doctor explained Fyodor Nikolai Kerensky's experiments with a time field in Paris, 1979 caused cracks in time. (TV: City of Death)
Charley Pollard described a time fissure, which the Eighth Doctor described as a "rent in the fabric of the Web of Time itself," as a "crack in time." (AUDIO: The Time of the Daleks)
The Tenth Doctor's TARDIS fell through a "crack in time" which led to Pete's World. (TV: Rise of the Cybermen)
After the Cardiff Space-Time Rift splintered, numerous temporal cracks widened resulting in objects and people from other time periods appearing all over the world. These cracks were used as a diversion by Bilis Manger, who manipulated Torchwood Cardiff into opening the rift, thus releasing Abaddon. The rift was closed back when Abaddon was killed by Jack Harkness, but was volatile as ever. (TV: End of Days)
Sarah Jane Smith observed that the Trickster manifested himself on Earth through a crack in time when he manipulated her into changing history by saving the lives of her parents Eddie and Barbara Smith. The Trickster was forced back when Eddie and Barbara chose to meet their established deaths, negating an alternate timeline in which he seized the planet. (TV: The Temptation of Sarah Jane Smith)
The time field caused by a total event collapse created "cracks in the skin of the universe," (TV: The Pandorica Opens) described by the Eleventh Doctor as "two parts of space and time that should never have touched." (TV: The Eleventh Doctor) When the Doctor initiated Big Bang Two to reboot the universe, River Song claimed that all the cracks would close. (TV: The Big Bang) However, one crack was known to remain above the planet Trenzalore, leading to Gallifrey's pocket universe. Ironically, it was the Kovarian Chapter of the Silence who were responsible for the cracks by causing the Total Collapse Event Incident in an attempt to prevent the Doctor from reaching Trenzalore. (TV: The Time of the Doctor)
Skak's attempts to release Ephnol from his temporal imprisonment caused a crack in time, which caused the temporal displacement of both the house of John O'Brien in 2009 and a Victorian house from 1884, swapping them. The Bannerman Road gang helped Deathy to close it before it spread all over the world. (AUDIO: The Ghost House)