Zero Plus Tick
On an exchange, a transaction in which a security was traded at the same price as its previous trade, which was in turn higher than the trade before that. Some regulations and rules on exchanges only permit certain transactions following a zero-plus tick or an uptick, though some, such as the short sale rule have become obsolete with increased digitalization of the market.
The sale of a security when the price is the same as the security's preceding sale price but is above the last different sale price. A short sale of a security is permitted on a zero-plus tick.