Question: We're creating a chart showing traffic by time of day over a given period. So the y-axis is traffic, the x-axis is midnight, 1am, 2am, etc. It could also be days of the week. What's the generic name for this type of chart? I've come up with "cycle chart". Is that the standard? Is there one?
![example](https://i.stack.imgur.com/IDu3k.png)

Update:

Just to add a bit more clarity, what's being shown in the top chart is *not* one day, it's an aggregation of many days. E.g. over the last month, 6am has on average been lower than noon. Similarly, in the bottom chart, over the last year, traffic dips on Saturdays.

Answer: 
Nick Cox [(*Stata Journal* 2006, p403)](http://stata-journal.com/sjpdf.html?articlenum=gr0025) calls this sort of plot a **'cycle plot'**, but notes that:

> 
> Cycle plots have been discussed under other names in the literature, including cycle-subseries plot, month plot, seasonal-by-month plot, and seasonal subseries plot.
> 
> 
> 

(followed by a load of refs to textbooks and papers)

Many of these are clearly specific to seasonality, i.e. periods of one year. I still like the suggestion of 'periodic plot/chart' that I made in a comment to the question, but it appears the questioner's original suggestion of 'cycle plot/chart' is in fact the more standard generic term.
I'd suggest "diurnal" or "circadian" rhythm chart. For weekly, the latter would be "circaseptan", "circamensual" for "monthly", and "circannual" for "yearly".