Increasingly, ultra-short pulses with pulse durations in the range of pico-/femtoseconds are used in laser applications. As such pulses are extremely short, there are specific advantages with regard to the technical and industrial applications (for example, processing of materials) and in the medical field (for example, ophthalmology and ENT surgery). Further assets and new applications arise from lasers emitting short pulses for information and communication technologies as well as for metrology and life sciences (for example, gentle observation of cellular processes). The development of the novel technical possibilities arising from those pulses is still in the beginnings and we can expect a high number of innovative applications. Previous investigations showed that the existing set of standards concerning laser characterization only covers parts of the novel short pulse laser technology and therefore should be expanded, because the test methods for ultra-short pulses are based on completely different effects compared with those for conventional lasers and many times non-linear processes are involved. In addition the terminology has to be clarified. This standard defines fundamental terms, symbols and units of measure for the characterization of short-pulse and ultra-short-pulse lasers (picosecond and femtosecond pulses, respectively). The main purpose of this document is a standardization of these terms and the provision of clear definitions for the same. The definitions in this document are applicable for all cases where no direct electronic measurements are available anymore. The committee responsible for this standard is NA 027-01-18 AA "Laser" ("Laser") at DIN.