Focal

(a.) Belonging to, or concerning, a focus; as, a focal point.

Thesaurus Entries

approaching, arch, asymptotic, banner, basic, bedrock, capital, cardinal, central, centralized, centred, centripetal, centrolineal, champion, chief, concentrated, concurrent, confluent, confocal, connivent, convergent, converging, crowning, dominant, essential, first, foremost, fundamental, great, headmost, hegemonic, indispensable, leading, life-and-death, life-or-death, magisterial, main, master, material, meeting, mutually approaching, of vital importance, overruling, paramount, predominant, preeminent, preponderant, prevailing, primal, primary, prime, principal, radial, radiating, ranking, ruling, sovereign, star, stellar, substantive, supereminent, tangent, tangential, topflight, uniting, vital