There isn't a single, universally recognized symbol for soluble. However, in chemistry, solubility is often indicated by the following:

* (aq): This abbreviation stands for "aqueous" and is used to indicate that a substance is dissolved in water. For example, NaCl(aq) represents sodium chloride dissolved in water.

* "soluble" written out: This is the most common and straightforward way to indicate solubility. For instance, you might say "sodium chloride is soluble in water."

It's important to note that the specific symbol or wording used to denote solubility can vary depending on the context and the specific chemical being discussed.