Question

full word of ' R' in organic chemistry

Answer 1

R is not a word it is a symbol showing

that R can be any chain of carbon for example esters are depicted by the formula RCOOR where the first and last R are the chain of carbon

Answer 2

An abbreviations for any group in which a carbon or hydrogen atom is attached to the rest of the molecular some time use more loosely to include other elements such oxygen, nitrogen.