While I know what you meant in the parent, "numeric timezone" isn't a thing. When it's in a numeric format the correct term is "offset". It cannot be referred to as a timezone as it's timezone will remain constant, but offset may change depending on the time of year (and the impact daylight savings has on the correct offset).

For what it's worth, i too hate when people say things like "EST","CST" etc. Not only are they difficult to remember, but they're ambiguous. i.e. AEST is Australian Eastern Standard Time, but no one includes the A when it's spoken and rarely when its written, which often means when two people over email say "lets talk at 9am EST", hopefully they're on the same continent, or they will miss each other by around ~14 hours.