>> IIRC, a "word" in the strictest sense is the size of a data entity that is directly addressible (i.e. minimal size of data entity that can be transferred between main memory and CPU register),
>>

I'm not sure why you said that. Can you elaborate a little more ?
There are these instruction stosb, movsb, lodsb. Not to mention that you can also use "byte ptr". AFAIK, it's the instruction to transfer a single byte from reg to mem and vice versa. And it is also still a valid instruction in 32bit machine.


>> On Intel 80x86 family of CPUs a "byte" is an 8-bit quantity, a "word" is a 16-bit quantity (two bytes), a "doubleword" is a 32-bit quantity (four bytes), and a "quadword" is a 64-bit quantity (eight bytes). Using typical Intel assembly-language nomenclature:
BYTE 8-bit
WORD 8-bit
DWORD 16-bit
QWORD 32-bit
>>

Since you mentioned assembly languange on 80x86, it's better to complete it:

unsigned                    signed
---------                  --------
BYTE           8 bit       SBYTE
WORD          16 bit       SWORD
DWORD         32 bit       SDWORD
FWORD         48 bit
QWORD         64 bit (1)
TBYTE         80 bit
Double QWORD 128 bit (2)

(1) - introduced on Intel 486
(2) - introduced on Intel PIII with SSE

Regards