What is the term for decreasing the number of bits required to illustrate data?

The term that describes the process of decreasing the number of bits required to represent data is compression. This involves reducing the size of a file or data set without losing the essential information it contains, which can make storage and transmission more efficient. Compression techniques can be either lossless or lossy; lossless compression allows for the original data to be perfectly reconstructed, while lossy compression permanently removes certain information, particularly in contexts like image and audio files, to achieve greater reductions in size.

In contrast, decompression refers to the process of taking compressed data and restoring it back to its original format. This is the reverse of compression, not the initial act of reducing data size. Encryption involves transforming data into a secure format to prevent unauthorized access, which does not relate to compressing the data size. Encoding is about converting data into a different format, often for compatibility or readability purposes, but it does not necessarily reduce the number of bits used. This context reinforces why compression is the correct answer for the question regarding reducing the number of bits.