Jealousy  Jealousy generally refers to the thoughts or feelings of insecurity, fear, and concern over a relative lack of possessions or safety. Jealousy can consist of one or more emotions such as anger, resentment, inadequacy, helplessness or disgust. In its original meaning, "jealousy" is distinct from envy, though the two terms have popularly become synonymous in the English language, with "jealousy" now also taking on the definition originally used for envy alone. Jealousy is a typical experience in human relationships, and it has been observed in infants as young as five months. Some researchers claim that jealousy is seen in all cultures and is a universal trait. However, others claim jealousy is a culture-specific emotion. Jealousy can either be suspicious or reactive, and it is often reinforced as a series of particularly strong emotions and constructed as a universal human experience. Psychologists have proposed several models to study the processes underlying jealousy and have identified factors that result in jealousy. Sociologists have demonstrated that cultural beliefs and values play an important role in determining what triggers jealousy and what constitutes socially acceptable expressions of jealousy. Biologists have identified factors that may unconsciously influence the expression of jealousy. Throughout history, artists have also explored the theme of jealousy in photographs, paintings, films, songs, plays, poems, and books, and theologians have offered religious views of jealousy based on the scriptures of their respective faiths. The word stems from the French "jalousie", formed from "jaloux" (jealous), and further from Low Latin "zelosus" (full of zeal), in turn from the Greek word ("zēlos"), sometimes "jealousy", but more often in a positive sense "emulation, ardour, zeal" (with a root connoting "to boil, ferment"; or "yeast"). The "biblical language" zeal would be known as "tolerating no unfaithfulness" while in middle English zealous is good. One origin word "gelus" meant "Possessive and suspicious" the word then turned into "jelus." Since William Shakespeare's use of terms like "green-eyed monster", the color green has been associated with jealousy and envy, from which the expressions "green with envy", are derived. People do not express jealousy through a single emotion or a single behavior. They instead express jealousy through diverse emotions and behaviors, which makes it difficult to form a scientific definition of jealousy. Scientists instead define jealousy in their own words, as illustrated by the following examples:     These definitions of jealousy share two basic themes.