Origin: Latin suffix -ment
Requirement has 4 different meanings across 1 category:
required activity
"the requirements of his work affected his health"
"there were many demands on his time"
anything indispensable
"food and shelter are necessities of life"
"the essentials of the good life"
"allow farmers to buy their requirements under favorable conditions"
"a place where the requisites of water fuel and fodder can be obtained"
something that is required in advance
"Latin was a prerequisite for admission"
A necessity or prerequisite; something required or obligatory. Its adpositions are generally of in relation to who or what has given it, on in relation to whom or what it is given to, and for in relation to what is required.
"The new safety regulation requires all employees to complete the training course within their first week of employment as a mandatory requirement."
In plain English: A requirement is something you must have or do to meet a rule or finish a task.
"The job posting lists a college degree as a basic requirement for applying."
Usage: Use in when referring to the source that imposes a requirement and on when indicating the person or thing subject to it. Avoid confusing this noun with its verb form by ensuring your sentence structure clearly identifies both the obligation and who must fulfill it.
The word requirement comes from combining the verb require with the suffix -ment to indicate an action or result. It entered English as a noun describing something that is needed or demanded.