1.  alpha and omega(n = noun.time) - the first and last; signifies God's eternity;
is a kind of eternity, infinity

2.  alpha and omega(n = noun.communication) - the basic meaning of something; the crucial part;
is a kind of crux, crux of the matter

N  whole, totality, integrity, totalness, entirety, ensemble, collectiveness, unity, completeness, indivisibility, indiscerptibility, integration, embodiment, integer, all, the whole, total, aggregate, one and all, gross amount, sum, sum total, tout ensemble, length and breadth of, Alpha and Omega, be all and end all, complex, complexus, lock stock and barrel, bulk, mass, lump, tissue, staple, body, compages, trunk, torso, bole, hull, hulk, skeleton greater part, major part, best part, principal part, main part, essential part, lion's share, Benjamin's mess, the long and the short, nearly, all, almost all, whole, total, integral, entire, complete, one, individual, unbroken, intact, uncut, undivided, unsevered, unclipped, uncropped, unshorn, seamless, undiminished, undemolished, undissolved, undestroyed, unbruised, indivisible, indissoluble, indissolvable, indiscerptible, wholesale, sweeping, comprehensive, wholly, altogether, totally, entirely, all, all in all, as a whole, wholesale, in a body, collectively, all put together, in the aggregate, in the lump, in the mass, in the gross, in the main, in the long run, en masse, as a body, on the whole, bodily, en bloc, in extenso, throughout, every inch, substantially, tout bien ou rien.

alpha, alpha blocker, alpha brass, alpha bronze, alpha centauri, alpha crucis, alpha decay, alpha fetoprotein, alpha foetoprotein, alpha geminorum, alpha globulin, alpha iron, alpha methyl dopa, alpha orionis, alpha paper, alpha particle, alpha privative, alpha radiation, alpha ray, alpha rays, alpha receptor, alpha rhythm, alpha software, alpha test, alpha wave, omega, omega centauri