While we're on the subject of words and grammar...is there a term for word meanings or usages that change with different generations. One recent example I've noticed is - "Really?"...as in "are you serious?" In the 70's we said "Really" as in "I totally agree". Another is "ridiculous", as in amazing or outstanding, and not ridiculous. We used to say, don't EVEN think about it...with the emphasis on EVEN. I guess every generation has their slang words such as groovy, hip, hep, cool,etc...but the examples I listed above are different...why...and is there a name for that?