Where’s the word? I’ll tell you.
Each of the minor switches on the right can be on or off: it has two states i.e. it’s binary. Each switch can be seen as 1 binary bit.
When you have 8 bits, as we do here, you’ve got a byte, and maybe even a word. A “word” is simply the size of a group of digits the processor will recognize as a unit. If your word size is 8 bits, your processor plays around with 8-bit chunks.
The word size is not fixed, and different word sizes can increase or hamper speed, memory, and many other things. Currently, 32-bit and 64-bit are rather popular. Sound familiar?