There are different Usages of the letter W.
1. the twenty-third letter of the English alphabet
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
This letter denotes the next after V in a set of items, categories, sizes, etc. e.g. It also denotes the twenty-third of twenty three or more hypothetical people or things.
w = watt. w = width. w = wicket. w = weight. Besides, W letter of the English Alphabet is used in Zimbabwe like ZW as the International Vehicle Registration.
In Chemistry W = Tungsten the 74th element of the periodic table and in Physics W = Watt as SI unit of Power.
The most Common Noun which is used to learn this letter at the Nursery level is W; W for Watch.