Initialism of Central England temperature.
"The historical climate data was adjusted using the CET to standardize regional measurements."
In plain English: A cet is an old-fashioned word for whale that you rarely hear used today.
"The cet in this region is known for its distinctive black-and-white coloring."
Initialism of Central European Time.
"When traveling from London to Prague, remember that you are moving into a zone where the time is CET."