normo

One root, and worth saying so, because the shape invites a decode that does not exist. There is no nor- and no -mo: normo came over whole from Latin norma, and so did normala at rank 1170. The two are relatives rather than a derivation, which is why the course teaches both instead of building one from the other.

The Latin is the good part. A norma was a carpenter's square, the L-shaped tool you press against a joint to see whether the angle is honest. Hold that picture and the whole family falls out of it: normala is what fits the square, nenormala is what does not, and English enormous is literally e-norm-is, out of the square, off the scale.

Three neighbours the course keeps apart. A regulo is a rule somebody wrote down and somebody else can enforce. A kutimo is simply what people do, with no claim that they should. A normo sits between them: the line that counts as acceptable, which the rule tries to codify and the habit usually tracks. When a committee publishes a technical specification it is a normo (la ISO-normo), and when a society expects you to queue it is also a normo. Same word, and the shared idea is the set square, not the sanction.