When you place an order that goes on the order book partially or fully (typically, in the context of Limit Orders and Stop-Limit orders placed via the trading screen that are set at a price that is not immediately filled), any subsequent trades coming from that order will be as a “maker" as the order will stay on the order book rather than being executed immediately.

In instances where an order fills partially, the portion of an order that fills immediately is subject to a taker fee, while the portion of an order that makes it onto the order book will be subject to a maker fee.

These orders add volume to the order book, helping to "make the market," and are therefore termed the "maker" for any subsequent trades.

Taker trades are when you place an order that trades immediately, by filling partially or fully, before going on the order book.

Trades from Market Orders are typically takers, as Market orders rarely go on the order book, except in cases where a large order cannot be filled immediately, and instead, are executed immediately.

These trades are "taking" volume, or liquidity, off of the order book, and are therefore called the "taker."

Limit IOC and Limit FOK orders (accessible via the API) are also always takers.

Fees for Maker and Taker transactions will vary depending on your 30-day trade volume, calculated on a trailing basis, and can be seen on the Binance.US Fee Schedule.