The term olds refers to a nebulous older generation of quiz bowlers relative to the perspective of a new, frequently high school player. Introduced by Justin French somewhat after the creation of more recent online quizbowl fora like the meme group and the Discord, the term has been adopted by many high school players (the youngs) who have taken it on as a group identity in the wake of new online spaces being created for them. It can take on negative connotations when associated with ingrained aspects of quiz bowl culture and with older communication mediums like the forums and the IRC.
Being an old requires community consensus. Retired and open players like Mike Cheyne and Andrew Yaphe, graduate students like John Lawrence and Jacob Reed, and tenured undergraduates like Charles Hang are definitively olds, but many undergraduate players are also considered to fall in the category, leaving the boundary vague. The term is old enough now that many of its original users (including Justin French, the popularizer of the term) now play college quizbowl - their status as old vs. young is unclear.