Pros: 1  Works equally well in open terrain, under cover or in a gym. 2  Accurate on flat or hilly terrain and when making quick, sharp turns (e.g., when trail running or on an indoor track). 3  Lightweight design is sleeker than most GPS-enabled SDMs.
Definitions for mass extinction. Here are all the possible meanings and translations of the word mass extinction. Wiktionary(0.00 / 0 votes)Rate this definition: mass extinction(Noun) A sharp decrease in the total number of species in a relatively short period of time.
extinction. 1  the act of extinguishing. 2  the fact or condition of being extinguished or extinct. 3  suppression; abolition; annihilation: the extinction of an army. 4  Biology. the act or process of becoming extinct; a coming to an end or dying out: the extinction of a species. 5. Psychology. the reduction or loss of a conditioned response as a result of the absence or withdrawal of reinforcement. 6. Astronomy. the diminution in the intensity of starlight caused by absorption as it passes through the earth's atmosphere or through interstellar dust.