What is the function of decimation?

In digital signal processing (DSP), decimation is the process of reducing the effective sample rate of a digital signal. It is accomplished by keeping only every Nth sample and discarding the rest, which effectively decreases the data rate and reduces the computational load on subsequent processing stages. While the word "decimation" historically means destroying one-tenth of something, in electronics it has nothing to do with converting data to decimal form, rounding off significant digits, or physically attenuating the analog signal's amplitude. It strictly refers to downsampling digital data.