Enabling one of 16 outputs for activation with a binary 4-lever input?
I'm using one lever for each bit. I have no idea how to make it so that flipping, say, bit 1 and bit 8 will make piston #9 go up when I hit "run".
I assume there's a standardized name for the thing I'm trying to build, but I have no clue what that might be.
The cirquit you are describing is called address decoder, which is a specific kind of binary decoder cirquits. Demultiplexer is also a very closely related cirquit. Searching for "minecraft decoder" brings tons of good results, you can start from there.