In this Chapter, unless the context otherwise requires,—
     (a) “employment in the national service” means employment in a notified establishment in pursuance of an order passed under section 23;
     (b) “employer” means any person who employs technical personnel to do any work in an establishment and includes any person entrusted with the supervision and control of technical personnel in such an establishment;
     (c) “establishment” means—
         (i) any office, or
         (ii) any place where any industry, trade, business or occupation is carried on; and includes any technical institution or training centre established, selected or approved by the Central Government;
     (d) “National Service Tribunal” means a Tribunal constituted under section 21;
     (e) “notified establishment” means any Government establishment and any establishment declared by notification under sub-section (1) of section 22 to be engaged in work of national importance;
     (f) “notified occupation” means any occupation which the Central Government may, by rules made under this Chapter, specify as a notified occupation for the purposes of this Chapter;
     (g) “technical personnel” means all persons who possess knowledge of or skill in one or more of the notified occupations, whether or not they are employed in any establishment, and includes such persons or class of persons undergoing training in any of those occupations in any establishment as may be declared by the Central Government by notification in the Official Gazette to be technical personnel for the purposes of this Chapter