What is the meaning of the sign in front of the vector in physics besides the direction of the quantity

What is the meaning of the sign in front of the vector in physics besides the direction of the quantity

Vector is a quantity with direction! It represents direction!

The physical meaning of vector product

The physical meaning of vector product depends on which vectors the vector product is composed of

Does the electric displacement vector have physical meaning?
Please explain the reason in detail.

In electromagnetics, the electric displacement vector D is introduced in the form of auxiliary field quantity. Although we can calculate the electric field strength e from the experimental relationship between D and E, actually D has no exact physical meaning

What is the meaning of "standard quantity"?

Standard quantity refers to the international standard unit: meter, kilogram, cubic meter, etc