What does UOM means and what is its role and use of it?What is default UOM and other UOM?

-UOM means unit of measurment. Your products, that you sell in KG, GM, LTR….or any other unit, then that is default unit.

-Other UOM: Currently no use. (But in future releases, you can ).

Ex: Many time it happens that one product is sold in different units like KG, GM and BOXES.
If KG is default UOM then grams and boxes becomes other UOM.