Core
Central
Synonyms: Central, basic, elemental, primary, chief, vital, number-one, nucleus, hub, marrow, essence, crux, pith, sum and substance, basis, cornerstone, mainspring, root, underpinning, essentials, main ingredients, nitty-gritty, nuts and bolts, basics, key, fundamental, principal, main, crucial, essential, heart, nub, kernel, meat, quintessence, gist, substance, body, bedrock, linchpin, foundation, base, fundamentals, basic principles, heart of the matter, brass tacks, and ABC.
Centre
Synonyms: Centre, middle, bosom, bowels, innards, interior, nucleus, recesses, depths, and midst.
Example Sentences
Trust is the core of relationships.
The core values guide our actions.
He has a strong core strength.
The core issue requires immediate attention.