Translation Unit (TU)
A segment of text treated as a single item for translation.
Definition
A translation unit (TU) is the smallest segment of content that is translated as a single item. Typically a sentence, phrase, or UI string. Translation units are the basic building blocks stored in translation memory—each TU pairs source text with its translation. The granularity of TUs affects translation memory leverage and consistency.
Examples
- →Sentence TU: 'Click the button to continue.'
- →UI string TU: 'Save'
- →Paragraph TU: (less common, harder to reuse)
- →TM entry: EN 'Hello' → ES 'Hola' (one TU)
Frequently Asked Questions
What is the ideal translation unit size?
For software: UI strings and individual sentences work best. Smaller TUs = better TM reuse. Larger TUs = better context but less reuse. Most tools auto-segment by sentence. Avoid translating word-by-word (loses context).
How do translation units relate to translation memory?
TM stores TUs. When new content matches a stored TU, TM suggests the translation. Exact match = same TU, fuzzy match = similar TU. More consistent TUs = higher TM leverage over time.