To store compactly in order to reduce the amount of memory required to hold the same data. There are several ways of doing this, for example by storing several bytes in one word or by replacing multiple occurrences of a character or word by a triplet consisting of

1. (a) a special code indicating the start of a triplet;

2. (b) a single instance of the replicated character or word;

3. (c) a count of the number of times the character or word occurs.