A derogatory term for drug-users at dance clubs. Most commonly employed when describing Methylenedioxymethamphetamine (Ecstasy) users. The term itself comes from the fluid head movements done by those described; appearing as though their neck is made of jelly.
"Yes, Jason and I used to hit the clubs all the time, but we have not since he became a jellyneck."
An acronym for "Believe it Comrade". (1) Used when someone questions the validity of a claim or statement that has been made. (2) Used to reinforce a claim or statement. See also (DNBiC].
Person 1: "I once saw the big boss glory hole a Roma Gypsy on a train to Slovakia"
Person 2: "No way!"
Person 3: "BiC!!!"