Predicate and predicator

Predicate : any word (or sequence of words) which (in a given single sense) can function as the predicator of a sentence.
Hungry, in, crook, asleep are all predicates.
Predicator : A word that does not belong to any of the referring expressions and which, of the remainder, makes the most specific contribution to the meaning of the sentence.
- asleep is the predicator in Mother is asleep.
- Love is the predicator in The tall boy loved the Japanese girl.
- Standing is the predicator in James was standing there.

The verb be in its various forms (is, was, are, were, am) cannot be a predicator.
The term predicate identifies elements in the language system, independently of particular example sentences. Predicator identifies the semantic role played by a particular word (or group of words) in a particular sentence. It is possible to show the predicator of a sentence, but impossible to list the predicators of English. A simple sentence only has one predicator, although it may contain more than one instance of a predicate.
A tall, handsome stranger entered the shop.
This sentence have only one predicator enter, but the sentence also contains the words tall, handsome, stranger, and shop.

Referent vs Reference

Reference vs. referent
Reference: relationship between piece of language and the things in the world.
Referent: A referent is concrete object or concept that is designated by a word or expression.
Example:
Princess Diana is the referent of Rose of England.
The relationship between Princess Diana and Rose of England is called reference.

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.