Middle English.

(idiomatic) In summary; ultimately.

The sharp edge of the blade of a knife or other cutting tool. / (idiomatic, by extension, often with "on the") The forefront, or position of greatest advancement in some field.

Alternative form of cutting-edge

(music) A blues form built on an eight-measure chord pattern, most typically I, I, IV, I, V7, IV, I, V7, where I, IV and V7 represent the tonic, subdominant and dominant seventh chords respectively.

(Christianity) The days leading up to the second coming of the Messiah (Christ), when the world will be judged. / (Islam) The days leading to the coming of the Mahdi.

(sociology) Use of numerical data to inform social programs.

present participle of social engineer

(historical) The empire ruled by the Achaemenid dynasty 550–330 B.C.E.. / (historical) The empire ruled by the Sassanid dynasty 224–651 C.E..

(masonry) In bricklaying, an arrangement of bricks such that one course has the short sides of the bricks (headers) facing outwards, and the next course has the long sides of the bricks (stretchers) facing outwards.