- cardinal, central, fundamental, key, primal - serving as an essential component; "a cardinal rule"; "the central cause of the problem"; "an example that was fundamental to the argument"; "computers are fundamental to modern industrial structure"
Antonym: unimportant (indirect, via important)
- cardinal - being or denoting a numerical quantity but not order; "cardinal numbers"
Antonyms: ordinal, zero, zeroth, first, 1st, second, 2nd, 2d, third, 3rd, tertiary, fourth, 4th, quaternary, fifth, 5th, sixth, 6th, seventh, 7th, eighth, 8th, ninth, 9th, tenth, 10th, eleventh, 11th, twelfth, 12th, thirteenth, 13th, fourteenth, 14th, fifteenth, 15th, sixteenth, 16th, seventeenth, 17th, eighteenth, 18th, nineteenth, 19th, umpteenth, umteenth, umptieth, twentieth, 20th, twenty-first, 21st, twenty-second, 22nd, twenty-third, 23rd, twenty-fourth, 24th, twenty-fifth, 25th, twenty-sixth, 26th, twenty-seventh, 27th, twenty-eighth, 28th, twenty-ninth, 29th, thirtieth, 30th, thirty-first, 31st, thirty-second, 32nd, thirty-third, 33rd, thirty-fourth, 34th, thirty-fifth, 35th, thirty-sixth, 36th, thirty-seventh, 37th, thirty-eighth, 38th, thirty-ninth, 39th, fortieth, 40th, forty-first, 41st, forty-second, 42nd, forty-third, 43rd, forty-fourth, 44th, forty-fifth, 45th, forty-sixth, 46th, forty-seventh, 47th, forty-eighth, 48th, forty-ninth, 49th, fiftieth, 50th, fifty-fifth, 55th, sixtieth, 60th, sixty-fifth, 65th, seventieth, 70th, seventy-fifth, 75th, eightieth, 80th, eighty-fifth, 85th, ninetieth, 90th, ninety-fifth, 95th, hundredth, centesimal, 100th, hundred-and-first, 101st, hundred-and-fifth, 105th, hundred-and-tenth, 110th, hundred-and-fifteenth, 115th, hundred-and-twentieth, 120th, hundred-and-twenty-fifth, 125th, hundred-and-thirtieth, 130th, hundred-and-thirty-fifth, 135th, hundred-and-fortieth, 140th, hundred-and-forty-fifth, 145th, hundred-and-fiftieth, 150th, hundred-and-fifty-fifth, 155th, hundred-and-sixtieth, 160th, hundred-and-sixty-fifth, 165th, hundred-and-seventieth, 170th, hundred-and-seventy-fifth, 175th, hundred-and-eightieth, 180th, hundred-and-ninetieth, 190th, two-hundredth, 200th, three-hundredth, 300th, four-hundredth, 400th, five-hundredth, 500th, thousandth, 1000th, millionth, billionth, trillionth, nth
- cardinal - (Roman Catholic Church) one of a group of more than 100 prominent bishops in the Sacred College who advise the Pope and elect new Popes
--1 is a kind of bishop
--1 is a member of Sacred College, College of Cardinals
--1 has particulars:dean; Bellarmine, Bellarmino, Cardinal Bellarmine, Roberto Francesco Romolo Bellarmine; Borgia, Cesare Borgia - cardinal number, cardinal - the number of elements in a mathematical set; denotes a quantity but not the order
--2 is a kind of number
--2 has particulars: frequency, absolute frequency; googol; googolplex- cardinal, carmine - a variable color averaging a vivid red
--3 is a kind of red, redness
- cardinal, cardinal grosbeak, Richmondena Cardinalis, Cardinalis cardinalis, redbird - crested thick-billed North American finch having bright red plumage in the male
--4 is a kind of finch
--4 is a member of Richmondena, genus Richmondena - cardinal number, cardinal - the number of elements in a mathematical set; denotes a quantity but not the order