Sentence:  Although <WSD>STEVE</WSD> has been documented by amateur night sky watchers for decades, it is an exciting new upper atmospheric phenomenon for the scientific community. 
Meaning of the word marked with <WSD> tags:  An aurora-like light found in southern Canada (consistently lower latitude, unlike the aurora borealis which is generally high latitude), composed of a glowing purple ribbon of light, with green spikes coming off obliquely parallel to each other, moving at about 6.5 km/s East to West. Presumably occurs in the southern hemisphere as well.