‘Searing’ is cooking the surface of a piece of meat at a high temperature until well browned. This technique enhances the flavour of the meat, leaves a flavoursome sediment in the pan that can be de-glazed and used for gravy, and makes the joint much more visually appealing once roasted.
-Heat a little oil in a pan over a high heat until the oil is smoking.
-Add the meat and fry until golden-brown.
-Continue turning and cooking the meat until browned on all sides.
Source: https://www.bbc.co.uk