what is the difference between compulsory/mandatory/obligatory?

Fart, pooping, and diarrhea.

Compulsory and mandatory are the same, as in necessary. Obligatory comes from the base word "oblige" so it's less forceful; should.

>>8690474
Compulsory - you are compelled to do it
Mandatory - you are mandated to do it
Obligatory - you are obligated to do it
Hope this helps!

>compulsory (adj.)
1580s, from Medieval Latin compulsorius, from Latin compulsus, past participle of compellere "to drive together, force, compel" (see compel).

>mandatory
1570s, "of the nature of a mandate," from Late Latin mandatorius "pertaining to a mandator," from Latin mandatus, past participle of mandare (see mandate (n.)). Sense of "obligatory because commanded" is from 1818.

>obligatory

c. 1400, from Old French obligatoire "creating an obligation, obligatory," and directly from Late Latin obligatorius "binding," from obligat-, past participle stem of obligare (see oblige).

>>8690759

(cont.)

>mandatory from Latin verb. "mando, mandare"

The etymology for "mandare" is as follows:
From manus (“hand, handwriting, power”) + dō (“I give, I offer or render”) or *-dō (“put”).

etymology for the Latin noun "manus" is as follows:

Etymology 1
From Proto-Italic *manus, from Proto-Indo-European *méh2-r̥ ~ *mh2-én-. Cognates include Ancient Greek μάρη (márē), Old Norse mund, Old English mund (contemporary English: mound).

>>8690474
Obligatory means you are morally required to do it. Mandatory means the rules or the people in authority say you have to do it. Compulsory means you are forced to do it.

That's context dependent