essentials

the fundamental items or principles

the absolute minimum necessary for survival or a task

to supply the necessary items, like food or shelter

to acquire knowledge of the fundamental aspects of something

to understand the most important parts of a subject or argument

to focus one's attention on the most important aspects

to bring with you only the most necessary items, especially for a trip

to include the most important topics in a course or discussion

to not have the necessary items or qualities for life or a task