I think you are asking about Sport weight yarn. Yarn can be divided into "weights" which refer to the diameter of the yarn. Yarn Council of America is attempting to standardize this system of weights (which really doesn't have to do with the actual ounces, pounds, grams or kilograms).
Therefore, a Sport-weight yarn would be one that could be called "Fine" (vs a lace or superbulky yarn), or #2-sized yarn or that it generally has 23-26 stitches per 4 inches (a standard gauge length and height), horizontally.
You can find more information by following the link I have attached to this answer.
Ring spun yarn is a type of yarn that is achieved by constantly twisting a rope of cotton fibers. This process significantly strengthens the yarn.
difference between spun yarn and filament yarn
Ring spun yarn is when the yarn is both twisted and wound at the same time. Open ended spun yarn is when the yarn is twisted by rotating at the hap or break in the flow.
A yarn. Hence- "spun".
Any fibre, regardless of the source -- natural or man-made, can be spun. Synthetic yarn contains no natural fibres.
Yarn is spun and then sold for craft use.
There are three commercial methods of spinning yarn into the product we see at the store. They are called Ring Spun, Rotor Spun, and Friction Spun. Each method produces different results in the yarn. Increasing the elongation percent in Ring Spun yarn requires a fiber preparation method of carding (brushing). This will produce a softer, longer yarn whis is best used for knitted items.
Individual fibers are spun into yarn.
yarn
The term ring spun means that the yarn was spun with a ring device. The handle has a soft touch to it. It results in the yarn being soft and very durable and strong.
yarn
There are three commercial methods of spinning yarn into the product we see at the store. They are called Ring Spun, Rotor Spun, and Friction Spun. Each method produces different results in the yarn. The full question, ring spun carded and combed, refers to the fiber preparation method of carding (brushing) and combing the fibers prior to spinning, in order to form a softer yarn which is best for soft knit items. The fibers are spun in a ring arrangement making it unnecessary for extra plies, so the yarn is much finer. There is also a downside to using ring spun, because the very process that causes it to be softer also causes the yarn to be more prone to breaking.
Your answer depends on the yarn. Yarn can be spun from animals, including hairy animals; plants, such as flax and cotton; and exotic sources such as silk worm cocoons. Fine yarn can also be spun from man-made fibres -- usually based in oil, and even metal.