A translation memory is a database that stores sentences, paragraphs or segments of text that have been translated before.
Each entry, or segment, in the translation memory includes the original language, known as the "source" and its translation, known as the "target". These pairs are called translation units, or "TUs".
Translation memories (commonly known as a "TM") are used with translation software, such as SDL Trados Studio, and automatically suggests stored identical or similar matches as new documents are translated. This means sentences, paragraphs or segments of text that have been previously translated never need to be translated again.
Translation memories support the localization process, dramatically improving the quality, speed, consistency and efficiency of every translation job.