tri-state RAM switch
The OE simply disables the output drivers so it can't drive the data bus, i.e. does not push high or pull low.
Therefore from the perspective of this memory chip, the bus is free so that some other device like the host CPU or another identical memory chip can drive the data bus for reading or writing.
Even if OE is high, the WE can be used to write data to this memory chip, the data is not written to memory without the WE being active.