Longman Dictionary of Contemporary English - leading

~1 adj only before noun 1 »MOST IMPORTANT/BEST« best, most important, or most successful  (the leading software provider in the domestic PC markets | a leading heart specialist) 2 leading edge a) technical the front edge of something b) the area of an activity where the most modern and advanced equipment and methods are used  (working at the leading edge of genetic engineering)  (- see also leading-edge) 3 leading light a respected person who leads a group or organization, or is important in a particular area of knowledge or activity 4 leading question a question that deliberately tricks someone into giving the answer you want 5 leading lady/man the woman or man who acts the most important female or male part in a film, play etc  (- see also leading article) ~2 n technical 1 lead (lead3 (1)) used for covering roofs, for window frames etc 2 the space left between lines of print on a page