Definition of 'At-Or-Better'
An order condition instructing a broker to only fill a transaction at a specific price or above it. Unlike a market order, an at-or-better order will expire if a specific price target is not met or exceeded. The percentage of at-or-better trades in the market compared to the overall number of trades depends on liquidity and the state of the economy.
Investopedia explains 'At-Or-Better'
If the price of a share of stock is falling, an investor is unlikely to be able to execute an at-or-better trade because buyers are more likely to wait in order to obtain a lower price.
For example, if a share is trading at $10, a trader can put in an at-or-better order to sell the security at $10.10. Any price greater than or equal to $10.10 will trigger a sale.