Sentence or phrase that is separated from the rest of a text based on language grammar rules such as punctuation.
Segment of a source text and its translation treated as a single unit of meaning.
A translation memory is a database of your company where all the translations including the source text have been saved. This memory is built by the translation agency for consistency purposes (it comes in handy when your company uses certain terminology). New documents that you need to have translated are going to be analyzed against the translation database to find sentences that have already been translated.