Hi! Fluid is a common state of certain substances, or a type of matter. Liquid is one of the three phases or state of matter. Fluids flow and has some viscosity (thickness). Liquids also flows and it has volume, but no definite shape. :)

June, from a scientific standpoint, gasses and liquids are both fluids. Official definition: A continuous, amorphous substance whose molecules move freely past one another and that has the tendency to assume the shape of its container; a liquid or gas. Liquid can also be a financial term, meaning "easily or quickly converted to cash." For example, a publicly traded stock is liquid, whereas a piece of land is not (most of the time). Colloquially, you can say fluid when describing someone's movements if they're very smooth or seem natural, such as "that dancer moved very fluidly in that performance." Hope this helps!

Hi June. :) When using "Liquid" and "Fluid" as nouns, they mean the same thing, though sometimes one word sounds more "right" than the other in a sentence. "Fluid" would be used more often when talking about medical or mechanical things. Liquid is slightly more common. Examples: "Please check the fluids in my car." "The injured man at the hospital needs more fluids." "Ice is a solid, water is a liquid, steam is a gas." "I spilled a green liquid on the table." Liquid and Fluid can also be used as adjectives, but that is less common. "Liquid assets", "Gender fluid", etc.