(noun) origin - jamaican 1980s. singular and plural.
1. An expression of support or encouragement.
2. An expression of remembrance.

origin - "Up" is an english term used to mean elevation. Therefore the term "big up" literally means to elevate highly or to a superlative degree.

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.

lots of props. sent through a messenger, such as the radio or a friend

a word used to show respect for a person

it means to give respect or to acknowledge someone

massive props to someone you respek.

Word means to applause some one on a good doing, to congratulate them.