law: 2. Definitions.-
  (1) In this Act, unless the context otherwise requires,-
  (a) "essential defence services" means-
  (i) any service in any establishment or undertaking dealing with production of goods or equipment required for any purpose connected with defence;
  (ii) any service in any establishment of, or connected with, the armed forces of the Union or in any other establishment or installation connected with defence;
  (iii) any service in any section of any establishment connected with defence, on the working of which the safety of such establishment or employee employed therein depends;
  (iv) any other service, as the Central Government may, by notification in the Official Gazette, declare to be essential defence services, the cessation of work of which would prejudicially affect the-
  (I) production of defence equipment or goods; or
  (II) operation or maintenance of any industrial establishment or unit engaged in production of goods or equipment required for any purpose connected with defence; or
  (III) repair or maintenance of products connected with defence;
  (b) "strike" means the cessation of work, go-slow, sit down, stay-in, token strike, sympathetic strike or mass casual leave, by a body of persons engaged in the essential defence services, acting in combination or a concerted refusal or a refusal under a common understanding of any number of persons who are or have been so engaged to continue to work or to accept employment, and includes-
  (i) refusal to work overtime, where such work is necessary for the maintenance of the essential defence services;
  (ii) any other conduct which is likely to result in, or results in, cessation or retardation or disruption of work in the essential defence services.
  (2) Words and expressions used herein and not defined but defined in the Industrial Disputes Act, 1947 (14 of 1947), shall have the meanings respectively assigned to them in that Act.