alpha and omega
1 the beginning and the end.
2 the essence or most important features.
☞ Alpha and omega are respectively the first and last letters of the Greek alphabet. Christians use the phrase as a title for Jesus Christ, taking it from Revelation 1:8: 'I am Alpha and Omega, the beginning and the ending, saith the Lord'.
❷1994BBC Holidays At Cambridge…you'll find the alpha and omega of American academic life: historic Harvard and space-age MIT (Massachusetts Institute of Technology).