orthophosphate

This term is used primarily in chemistry, agronomy, and geology to describe a specific chemical structure where the phosphorus atom is centrally located. It is distinguished from pyrophosphates or polyphosphates by its single phosphorus atom per molecule, making it the most common form of phosphorus found in biological systems and mineral deposits.

In a technical or laboratory context, the word is treated as a mass noun referring to the chemical species or the substance in general. It is rarely used in plural form unless referring to different types of orthophosphate salts (e.g., comparing various potassium orthophosphates).