There exist so many different naming conventions for database objects, none of them is wrong. It's more of a personal preference of the person who designed the naming convention.
Tables represent the instances of an entity.
For example, you store all your customer information in a table. Here, 'customer' is an entity and all the rows in the customers table represent the instances of the entity 'customer'. So, why not name your table using the entity it represents, 'Customer'. Since the table is storing 'multiple instances' of customers, make your table name a plural word. So, name your customer table as ' Customers '.