Auspicious is an adjective that means favorable, prosperous, or indicative of success.
Auspicious comes from Latin auspicium, which means “reading the future from the flight of birds.” The -ous is the English suffix, which indicates it's an adjective.
The history behind the word auspicious comes from Ancient Rome. The flight of birds was often considered a sign from the gods, so if a bird swooped down or flew up from the ground to the sky, this action could indicate good or bad luck for a person. However, only certain people, called “auspex”-es (auspices) could read these signs. The word auspex means “bird observer.” It comes from Latin avis (bird) and specere (to see). Due to these especially talented people, the act of predicting the future came to be known as auspicium. Auspices foretold the future before each important event in a person’s life. There were two types of ancient auspices: ex caelo (sky), and ex avibus (birds). Ex caelo observed events occurring in the sky, like lightening and thunder. Ex avibus were auspices that examined the actions of birds. Despite the fact that, in Ancient Rome, auspices could predict good or bad events, when the word came into use in the English language, it was only used to speak of favorable outcomes.
Today, we use auspicious to mean favorable or successful endeavors. For example, one may say, “The stock broker has had an auspicious year,” or “This semester included a very auspicious beginning.” Some cultures believe in “auspicious wedding dates,” which are certain days that are luckier to marry on than others. For example, an analysis of the Chinese calendar provides insight to the luckiest days on which to marry. In the Hindu culture, Akshaya Tritiya (celebration of the Lord Vishnu and Goddess Lakshmi, usually occurring at the end of April or beginning of May) is one of the four luckiest days on which one could marry.