Have you heard of a yarn count? in specific have you thought what it means when you hear counts like Ne 30s , Ne 20s , Nm 30s ( list goes on...).

To make it simple I will use a simple term.... 

Do you like to wear a thick piece of cloth as your inner wear? For sure , not.. you would prefer preferably thinner cloth. The difference between a thinner and thicker cloth is the yarn used to make the fabric. How to differentiate one yarn to other? Here the numbering systems of a yarn comes. 

Wide range of numbering systems followed worldwide. Most commonly used yarn numbering system is English Count  ( Ne ) for regular short stable spinning, In case of worsted yarns or long stable spinning , Metric System ( Nm ) is widely used. What is that? How to differentiate between both? 

A definition of Yarn Count is given by the Textile Institute  (UK) : Yarn Count is number indicating the weight per unit length or the length per unit weight of yarn.