There isn't a single, universal symbol for "declaration" in physics. The term "declaration" isn't typically used in a formal sense within physics equations or concepts.

However, depending on what you mean by "declaration," there are symbols used for related concepts:

* Defining a variable: You often use an equal sign (=) to define a variable, like "v = 5 m/s" where v is the velocity.

* Stating a law or principle: You might use a symbolic representation of the law itself. For example, F=ma for Newton's second law of motion.

Could you provide more context about what you're looking for?

For example:

* Are you trying to declare a new variable or constant?

* Are you trying to state a physical law or principle?

* Are you trying to make a specific statement about a physical system?

Providing more information will help me give you a more precise answer.