| Not opt. |
| Opt. opp. |
| Off. order |
| Need (abbr.) |
| Opp. of opt. |
| Needed: Abbr. |
| Basic, in coll. |
| Mandated: Abbr. |
| Petition: Abbr. |
| Mandatory: Abbr. |
| Necessary: Abbr. |
| Necessity: Abbr. |
| Mil. supply order |
| Course list abbr. |
| Not optional: Abbr. |
| Not elective: Abbr. |
| R.S.V.P., for instance |
| Mandatory coll. course |
| Must-take coll. course |
| Like some coll. courses |
| Like core coll. courses |
| Like some univ. courses |
| Not an elective (Abbr.) |
| Like core courses: Abbr. |
| Mil. demand for supplies |
| Strictly mandated (abbr.) |
| Like basic courses: Abbr. |
| Not elective, as a class: Abbr. |
| Abbr. in some class descriptions |
| What an asterisk means on some forms: Abbr. |