Today, we all agree that "byte" means 8 bits. But half a century ago, this was not so clear and the different hardware manufacturers were battling it out with different sized bytes.

A reminder of that past history is that in Internet standards documents, the word "octet" is used to unambiguously refer to an 8-bit byte. Also, "octet" is the French word for byte, so a "gigaoctet (Go)" is a gigabyte (GB) in English.

(Now, if only we could pin down the sizes of C/C++'s char/short/int/long/long-long integer types...)

An octet is unambiguously Latin for 8 of something; instruments, players, people, bytes, spider's legs, octopus' arms, molecules (see: octane).

Octad/octade was unambiguously about 8 bit bytes, but fell out of popular usage.

The term "octet" is still widely used in protocol descriptions and some other fields (source: All those interface specifications I have to read through my job)