requisite

A formal or fancy word for indispensable, requisite is often now used in a humorous context. During their princess phase, three year old girls are loathe to leave the house without the requisite beads, tiaras and high heels.

To remember this word, notice how similar it is to required. College students looking to sign up for classes they find interesting often bump up against the word prerequisite, which refers to a list of classes they will need to take before the one they're interested in.

Definitions of requisite
1

adj necessary for relief or supply

Synonyms:
needed, needful, required
necessary
absolutely essential

n anything indispensable

“a place where the requisites of water fuel and fodder can be obtained”
Synonyms:
essential, necessary, necessity, requirement
Antonyms:
inessential, nonessential
anything that is not essential
Types:
desideratum
something desired as a necessity
must
a necessary or essential thing
need, want
anything that is necessary but lacking
Type of:
thing
a separate and self-contained entity