As per Wikipedia, a collar is the part of a shirt that fastens around or frames the neck. A collar is separated from other necklines such as revers or lapels, by being made form a separate piece of fabric, rather than a folded or cut part of the same piece of fabric.
Now that we have defined a collar and know how it’s made, about time we realise its importance as well. Considering the fact that a collar is the most visible part of a shirt, it has to be one of the most important elements which define your overall look.
A collar not only defines a shirts formality, it also enhances your facial features at the same time. In essence, this means that getting your collar right is the most important step in designing a shirt, obviously after you’ve chosen the fabric.