Viz. is an abbreviation used similar to i.e. or e.g., but less commonly and with the intention of further explaining something mentioned earlier. For instance, you might say I study linguistics, viz. etymology and conlanging. Originally, the term was Tironian shorthand for the Latin word videlicet, which essentially means “namely” or “that is to say”. It is interesting to note that videlicet is a contraction itself, combining the words videre and licet, which meant “to see” and “allowed”, respectively (thus, videlicet translates to “it is allowed to see”). Videre, from Proto-Italic wideo, can be traced back to the Proto-Indo-European word weyd, with the same meaning, while licet is believed to have origins in Proto-Indo-European leyk, which meant “to prepare for sale” (it was related to auctions).
