The "Dark Ages" usually refers to a subset of the Middle Ages, the earlier part, so "for example" worked for me and I only stopped and realized that ie was mean

The "Dark Ages" usually refers to a subset of the Middle Ages, the earlier part, so "for example" worked for me and I only stopped and realized that ie was meant after reading your comment. This is one of those stupid things about English that make life for pupils harder for no reason. In most languages the abbreviation is straightforward and based on the actual language. (Also spelling bees don't exist in most other places). Entire classes of error possibilities are just made up for no good reason in English. (also, it's orthogonal, not orthagonal)