- 1[usually before noun] (geology) connected with the Ice Age the glacial period (= the time when much of the northern half of the world was covered by ice)
- 2(technology) caused or made by glaciers; connected with glaciers a glacial landscape glacial deposits/erosion
- 3(formal) very cold; like ice synonym icy glacial winds/temperatures the glacial waters of the Arctic The dining room was glacial.
- 4(formal) (of people) cold and unfriendly; not showing feelings synonym icy Her expression was glacial. Relations between the two countries had always been glacial.
- 5very slow The workers were making progress on the new house, but it was at a glacial pace.