I don't see three arrows down as any typical proofreading mark. Is it possible that what you are seeing as three down arrows is an indication to insert quotation marks? That's the closest idea that I can come up with. You may need to consult with your proofreader to clarify the symbol. (If someone's willing to read and make marks on your work, s/he will be happy to clarify those marks' meanings.)
It means traffic can pass on either side of an obstruction such as an island.
A yellow sign with two arrows pointing in opposite directions means there is a divided highway ahead.
Two arrows pointing in opposite directions usually symbolize balance or opposition. It can indicate a state of equilibrium or a binary relationship where two forces are working in opposition.
It can go in either direction i think Thomassen
The down arrows are there to scroll down to continue typing up the message.
Two arrows pointing at each other is a common symbol representing a two-way relationship or interaction, often indicating give and take, balance, or mutual influence between two elements.
A downward pointing triangle is often used to represent "female".
I think the "Fallout Shelter" sign
the arrows mean "is eaten by" so for example, if there is a picture of a rabbit with a arrow pointing to a fox it would mean that the rabbit "is eaten by" the fox
Tire Pressure
the arrows in a food chain mean "is eaten by" for example: grass----->rabbit----->fox the grass is eaten by or consumed by the rabbit. the rabbit is then consumed or eaten by the fox hope this helps
low coolant level