A translation memory, or TM, is a database that stores “segments”, which can be sentences, paragraphs or sentence-like units (headings, titles or elements in a list) that have previously been translated, in order to aid human translators. The translation memory stores the source text and its corresponding translation in language pairs called “translation units”. Individual words are handled by terminology bases and are not within the domain of TM.
Computer assisted translation (CAT) tools are based on translation memories. They help translators to remember previous translations and also operate as a more consistent team.