A strong inequality in which 
is not only less than 
, but much less (by some convention) is denoted 
.
Much Less
See also
Less, Much GreaterExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Much Less." From MathWorld--A Wolfram Web Resource. https://wwn.ikan3.com/7hz2929k26_9nqeuhigsnjcgsjpnuemse/MuchLess.html