Sheet lightning, also known as heat lightning, is a weather phenomenon that produces lightning flashes that are visible but do not contain thunder. The spelling of 'sheet' is transcribed as /ʃiːt/, with the 'iː' indicating a long 'ee' sound. 'Lightning' is transcribed as /ˈlaɪtnɪŋ/, with the stress on the first syllable and a long 'i' sound. The word 'sheet lightning' originated from the idea that the lightning appears like a large sheet across the sky, making it an incredibly fascinating meteorological occurrence to witness.
Lightning which appears in wide extended flashes, not forked.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.
The word "sheet" in "sheet lightning" refers to the appearance of the lightning, which resembles a bright, glowing sheet or flickering curtain of light in the sky. The term "sheet lightning" originated in the 17th century and comes from the Middle English word "schete", meaning a large, wide surface or expanse. This term was later influenced by the Old English word "scēat", which meant a sheet of cloth or a skirt. Thus, "sheet lightning" describes the visual effect of lightning spreading across the sky in a horizontal, curtain-like manner.