Sense and Reference

Reference : relation between piece of language and the things in the world. A referent is concrete object or concept that is designated by a word or expression, for example :
Historically, there was only one person called George Washington, the first president of US, but he can be referred to in a text in many ways, such as:
- the president
- Mr. Washington
- he
The different reference can have the same referent.
Example : morning star and evening star, both of which refer to planet Venus.
Sense : its place in a system of semantic relationships with other expressions in the language. Sense consists of 'semantic properties'. Example:
Woman has a sense of animate, female, married.
Girl has a sense of animate, female, unmarried.
To know what a woman means, you have to know what a girl means, so that you get the idea why a woman is different from a girl.
To make it simple, sense is the meaning of an expression, and if an expression refers to something, it has reference.