Tokens are a reperesenation of particular eset or utility, that usully rides on the top pf another blockchain. In most cases tokens are created and distributed trought ICO or IPO. Altcoins are separate currencies with their own blockchain. Zen is not premine nor ICo IPO. ZenCash is a platform designed for private communications and private economic activity. Zen started its life chainspliting from ZCL.  ZCL is forked from ZCash and ZCash is direct fork from Bitcoin. Zen is improved Bitcoin.