What ⋘ means
It says one quantity is very much smaller than another. The three chevrons strengthen one ordinary less-than comparison; they do not make three separate comparisons.
The plain-text << is also used for “much less than,” but repeated less-than marks have specialist uses too, including notation for growth rates and absolute continuity, a property of functions. Read the surrounding formula to tell which meaning applies.
Where does the less-than sign's history begin?
Thomas Harriot's algebra records the ordinary less-than sign. His algebra was published after his death in 1631.
Don't confuse it with
3Questions people ask
1Why does ⋘ show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type ⋘
⋘\22D8Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.