Objective Noun (-endus)

It all starts with the gerund. In English, a gerund is a verbal noun ending in “-ing”, not to be confused with a present participle.

I like running.
I like running water.

In Latin, a gerund is a verbal noun, too, only ending in “-endum”. As far as I can tell, it has pretty much the same meaning as the supine, and you just use one or the other depending on the grammatical construction. I could be wrong about that, though. In any case, Latin gerunds don't show up in English very often, so I won't say anything more about them.

However, just as a supine, ending in “-um”, can be made into a perfect participle, an (objective) adjective ending in “-us”, so also can a gerund be made into a gerundive. A gerundive is an objective adjective with the implication that a thing can or should be done. For example, the gerund “mirandum”, derived from the verb “miror”, “I marvel (at)”, becomes the gerundive “mirandus”, meaning something along the lines of “worthy of being marveled at”.

Once you have an adjective, of course, you can make it into a noun by having it refer to an unspecified thing, so “mirandus” can also be thought of as a noun, meaning “a thing that can or should be marveled at”. That noun is the objective noun I wanted to talk about.

Latin objective nouns don't show up in English all that often, but they do appear, and when they do, they drop the suffix “-us”. Here are a couple you might remember from arithmetic.

subtraho	I remove	subtrahendus	subtrahend
minuo	I diminish	minuendus	minuend

So, the subtrahend is the thing that should be removed, and the minuend is the thing that should be diminished … now I can finally remember which is which.

Sometimes, an objective noun is formed from a gerundive with a suffix other than the masculine singular “-us”, and when that happens, the suffix stays on even in English. Here are some familiar examples that use the neuter singular and plural.

do	I give	datus	datum, data
memoro	I mention	memorandus	memorandum, memoranda
ago	I do	agendus	agenda

My favorite example uses the feminine singular “-a”: the name “Amanda” literally means “she who must be loved”.