<mathematics> The number of prime numbers less than x is
about x/log(x). Here "is about" means that the ratio of the
two things tends to 1 as x tends to infinity. This was first
conjectured by Gauss in the early 19th century, and was
proved (independently) by Hadamard and de la Vall'ee Poussin
in 1896. Their proofs relied on complex analysis, but Erdös
and Selberg later found an "elementary" proof.

(From TV programming) Normal high-usage hours on a
time-sharing system; the day shift. Avoidance of prime time
was traditionally given as a major reason for night mode
hacking. The rise of the personal workstation has rendered
this term, along with time-sharing itself, almost obsolete.
The hackish tendency to late-night hacking runs has changed
not a bit.