1.Definition: most important element

"Policemen were primary targets"

Related Adjective(s):chief, main, master, principal

2.Definition: not derived from or reducible to something else; basic

"A primary instinct"

3.Definition: of first rank or importance or value; direct and immediate rather than secondary

"Primary goals", "A primary effect", "Primary sources", "A primary interest"

4.Definition: of or being the essential or basic part

Related Adjective(s):basal, elemental, elementary