These terms can be used in relation to the motherboard also, for example, my college uses 8085 processors in conjunction with what's called a TomAL motherboard.
With TomAL, the information on the data bus is time-multiplexed - the same bus lines carry either the 8 data bits or the lower 8 address bits (A7-A0) at any given time. Peripheral devices know whether it is data or an address using signals generated by the CPU.
The TomAL board employs three chips for bus buffering - there are two 8-bit DFF's (effectively registers) one which holds the higher 8-bits of an address (A15-A8) and another which holds the data of the address/data bus. There is a third, a so-called tri-state, which also holds the data of the address/data bus, but the data it holds is only valid if it is the lower 8 address bits. Otherwise, this chip outputs a signal equivalent to a "don't care" output.
Bus buffering is simply "holding" the data that was on the bus at any point in time. A "buffer" will hold the value that was last written to it until the write line of that "buffer" is set to 1, at which time the contents of the buffer will be set to whatever data is being fed into it. When the write line is set back to 0, the "buffer" will now hold the new value (that is, output the new value), regardless of what data is being fed into it, until the write line is again toggled to 1.
Hope this helps.