Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. The English language draws a terminological distinction (not all languages do) between translating (a written text) and interpreting (oral or sign-language communication between users of different languages); under this distinction, translation can begin only after the appearance of writing within a language community.
Lithium-ion (Li-ion) batteries have revolutionised portable consumer electronics from cameras to cell phones to laptops. Validated safety testing of larger, higher-energy installations has paved the way to large-scale stationary applications as well.